FILED
SEPTEMBER 10, 2026
In the Office of the Clerk of Court WA State Court of Appeals, Division III
IN THE COURT OF APPEALS OF THE STATE OF WASHINGTON DIVISION THREE
STATE OF WASHINGTON, ) No. 40274-6-III )
Respondent, )
)
v. ) UNPUBLISHED OPINION )
RICHARD J. AGUIRRE, )
)
Appellant. )
MURPHY, J. —Richard Aguirre appeals his conviction after a bench trial for first degree murder. He contends the trial court abused its discretion by admitting DNA evidence derived from a condom and from a bag that the condom was placed into when the condom was discovered at the crime scene. Aquirre further argues the evidence was insufficient to prove identity or premeditation. We disagree and affirm.
FACTUAL BACKGROUND
On January 30, 1986, at approximately 10:30 p.m., the body of 27-year-old Ruby Doss was found in an industrial area near the intersection of North Fiske Street and East Ferry Avenue in Spokane. It was later determined that the cause of death was blunt force trauma to Doss’s head and manual strangulation. The area where Doss was found was known for prostitution.
State v. Aguirre Doss’s pants were buttoned but unzipped. Straw was in her hair and on her body, though none was found in the immediate vicinity where the body had been discovered. Debris on Doss’s boots and pants indicated a struggle had taken place. Because of the cold, dark, and rainy conditions, with little ambient light, detectives secured the scene and returned at daylight the next morning to continue their investigation.
Detectives learned Doss was a sex worker who lived with her boyfriend and a daughter. The boyfriend described the clothing Doss wore that night, including a wig and mismatched earrings, and stated she carried a kitchen knife for protection. He confirmed that Doss typically purchased condoms in advance of meeting someone and charged $50 for the encounter. An employee at an adult bookstore, the last person other than the assailant known to have seen Doss alive, confirmed she purchased a condom shortly after 9:00 p.m., approximately 90 minutes before Doss was found dead.
The investigation after daylight returned on January 31 revealed a manure and straw dumping area roughly 250 feet from where Doss had been found the night before. Shoe and/or boot prints and tire tracks were present. Detectives recovered several of Doss’s personal items from the straw—her wig, a steak knife, coats, mismatched earrings, and a crumbled $50 bill. Nearby, the detectives found a condom they described
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State v. Aguirre as “very fresh,” with no dirt on it and ejaculate that appeared recent. 1 1 Verbatim Rep. of Proc. (VRP) (Nov. 30, 2023) at 355. The condom was collected using gloves, placed in a paper evidence bag, labeled “Item No. 17,” and secured in police property. 1 VRP (Nov. 29, 2023) 195-96. Detectives concluded a struggle occurred in the manure pit, and then Doss fled and was pursued over 200 feet to the location where she ultimately died.
A forensic pathologist 2 determined the cause of death to be blunt force trauma to the head (at least four blows) and asphyxia. The hyoid bone in the neck was fractured, which required substantial force. The pathologist testified strangulation requires sustained pressure for a minimum of three to four minutes, although the time to death can lengthen if the victim struggles or if the assailant’s grip changes.
In March 1989, the paper evidence bag containing the condom was hand-delivered by Lieutenant James Hill of the Spokane Police Department to Lifecodes Corporation
1 Although the defense attempted to establish there were other condoms at the crime scene, the evidence presented supports the opposite. Detectives confirmed no other condoms were observed at the crime scene and testified that if other condoms had been present, then they also would have been collected as evidence.
2 At the time of trial in 2023, Veena Singh, M.D. was the chief medical examiner for Spokane County. The pathologist who performed the autopsy on Doss in 1986 had since died, and once the trial court proceedings for this case began, Dr. Singh was asked to review the original case materials and reach a conclusion as to the cause and manner of Doss’s death. Dr. Singh conducted a forensic review of the 1986 materials including the coroner’s report and a photograph from the crime scene, and the autopsy report and photographs from autopsy, and offered medical findings and opinions at trial.
4
State v. Aguirre (Lifecodes), a private laboratory in New York, for restriction fragment length polymorphism (RFLP) testing. 3 Lisa Bennett, a forensic scientist at Lifecodes, testified at trial in 2023 and described that an evidence technician, Regina Palmer, would accept incoming items received by mail or hand delivery, write everything needed for chain of custody, and then assign an analyst for testing. Bennett followed a protocol, that to her recollection contained 63 steps and could take as long as 6 weeks to complete, 4 to obtain a DNA print. She placed the condom in a test tube with an aqueous solution (purified water) and agitated it to wash off all biological material. She spun the resulting solution in a centrifuge to divide out the high molecular weight DNA (from sperm) from low molecular weight DNA. Her testing determined there was insufficient high molecular weight DNA to create an RFLP DNA print. Bennett discarded the condom after determining all biological material had been removed, i.e., the condom was “consumed.” 2 VRP (Dec. 11, 2023) at 774, 815. At the time, this was the common practice.
3 RFLP testing is not currently used, but in 1989 it was considered cutting edge technology in the field of DNA identification. This testing is a molecular technique in which DNA is cut into distinct fragment sizes with restriction enzymes used to separate the fragments by length via yield gel electrophoresis. The resulting DNA extraction is used to isolate and purify genomic DNA from a sample. RFLP required a relatively large amount of high-quality DNA (at least a microgram).
4 The details of the protocol were not available to the parties through discovery or produced at trial. Witnesses at trial who had been associated with Lifecodes, which had since been sold to another company, testified the protocol was no longer locatable.
5
State v. Aguirre The empty package, Item No. 17, was returned to the Spokane Police Department and checked back into the property room.
In 1999, Detective Rick Grabenstein, who was part of the Spokane County Sheriff’s Office major crimes unit, learned Lifecodes retained DNA extracts generated from the 1989 testing. In 2001, he obtained those extracts and booked them into evidence as “Item No. 57.” 1 VRP (Dec. 5, 2023) 455-56, 471. Grabenstein sent the DNA extracts to Bode Technology Group (Bode) for short tandem repeat (STR) testing. 5 DNA analyst Michelle Galusha at Bode called Grabenstein before testing began because the extracts received were not accompanied by any reagent blanks. 6 Testing was later completed with no reagent blanks having been produced by Lifecodes. 7
5 STR testing looks for locations on our genes that repeat in a unique manner.
With such testing, the first step is extraction, which means getting the DNA out of the sample. The second step is quantitation to know how much DNA is present, with the following step known as amplification in which the process of polymerase chain reaction (PCR) is used to chemically amplify the specific areas of DNA of interest. The final step is detection of the DNA profile. In 1989 there was no process available to replicate DNA. With STR and PCR, the size of a DNA fragment could be a few hundred base pairs in length, as opposed to the several thousand necessary for RFLP testing.
6 Reagents are chemicals used during the testing process to assist in isolating DNA from the sample provided. A reagent blank helps ensure that the reagents (chemicals) being used are not contaminated with some other DNA. The purpose of retaining reagent blanks is for quality control in that anyone conducting additional DNA testing can be assured that the previous work was not contaminated.
7 There was no requirement in 1989 that laboratories retain reagent blanks and it is still not mandatory to do so. The retention requirement began to be written into protocols for laboratories in 2009 for work to examine older extracts.
6
State v. Aguirre The STR testing by Galusha resulted in a complete male DNA profile from the sperm fraction. The profile was later uploaded to the Combined DNA Index System (CODIS), a national database of DNA profiles received from various sources. An insufficient amount of DNA from the nonsperm fraction (possible female DNA profile) was present to develop a profile.
In 2008, Detective Kip Hollenbeck of the Spokane Police Department sent the DNA extracts and other items of evidence to Orchid Cellmark, a private laboratory in Texas that was under contract with the Washington State Patrol Crime Laboratory (Crime Lab). Orchid Cellmark obtained a complete male profile from the sperm fraction of Item No. 57 (the extracts), and partial male profiles from two other items of evidence. Aguirre was later excluded as a contributor to those other items. As with Bode, no female DNA profile was obtained from the nonsperm fraction. The Crime Lab confirmed the complete male profile met criteria for upload into CODIS and verified this profile was already in CODIS from Bode’s earlier testing.
Testing at Orchid Cellmark established that Crime Lab technician William Morig’s DNA was on Doss’s jacket and blouse. At the time the evidence was collected in 1986, DNA testing was not prevalent and stringent protocols to prevent contamination or cross-contamination of evidence had not yet been implemented.
7
State v. Aguirre On January 30, 2015, the Spokane Police Department was notified that a CODIS hit matched the DNA profile to Richard Aguirre. This was the first time Aguirre had been associated with the case. Subsequent investigation showed that in 1986, Aguirre was stationed at Fairchild Air Force Base and living in Spokane. A buccal swab collected from Aguirre pursuant to a search warrant confirmed the DNA profile match. Investigators interviewed Aguirre’s acquaintances, coworkers, a former romantic partner, friends, and others who knew him in 1986.
Ryan Flanagan, who worked with Aguirre at the Pasco Police Department and characterized their relationship as close, testified that Aguirre had brought up the Doss murder and said: “‘I fucked the bitch, but I didn’t kill her,’” and that he had met with her on more than one occasion. 2 VRP (Dec. 6, 2023) at 624.
Lawrence Kurt Cole, a lifelong friend, testified that between 1986 and 1988 Aguirre told him he had hit and choked an unnamed woman, but she was moving when he left. Cole said the statement made him sick to his stomach, and he was relieved to report it to law enforcement.
James Brian Vaught, another Pasco Police Department coworker, testified Aguirre showed him a newspaper article naming Aguirre as a suspect, said he knew Doss as a “‘woman of the night,’” and “‘she was alive when I left.’” 2 VRP (Dec. 7, 2023) at 704. Vaught did not interpret the last statement at the time it was made as serious. Aguirre told
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State v. Aguirre Vaught he always used a condom and did not know why his DNA would be associated with the Doss crime scene.
Joan Thomasson, who dated Aguirre beginning in 2010, testified that after reading a 2015 newspaper article, she contacted Hollenbeck and reported that Aguirre had said he thought he knew Doss and mentioned a condom.
In 2017, Hollenbeck arranged for the Crime Lab to examine the original paper evidence bag that had held the condom (Item No. 17). Forensic scientist Lorraine Heath cut the bag such that she could open it like a book and take swabs. She was specifically looking for female DNA. Given that more sensitive DNA testing had become available through probabilistic genotyping, it was thought a profile might be produced.
Probabilistic genotyping allows nuanced interpretation of low-level and mixed DNA samples. The two primary probabilistic genotyping software programs available are TrueAllele from Cybergenetics and STRmix. In 2017, the Crime Lab was still in the process of validating probabilistic genotyping for use in its own facilities, so Heath sent raw data from the swabs, along with reference DNA samples from Doss and Aguirre, to Cybergenetics for analysis. Preliminary results indicated Aguirre’s DNA was found on the nonsperm fraction; Doss’s DNA was not. Heath questioned how the data was used and interpreted by Cybergenetics because Cybergenetics did not use a threshold to differentiate instrument noise from DNA.
9
State v. Aguirre In 2018, the Crime Law implemented STRmix software for probabilistic genotyping. STRmix is generally accepted in the scientific community, and the protocols used are similarly accepted. Heath performed the analysis. Assuming a two-person mixture, the nonsperm fraction profile was 8,100 times more likely to be that of Aguirre and Doss, than Aguirre and an unknown person.
The defense in its case-in-chief presented its own forensic DNA expert, Dr. Ruth Ballard, who raised concerns about low-level mixture DNA, the absence of reagent blanks from the 1989 testing at Lifecodes, possible contamination (including Crime Lab technician Morig’s DNA on Doss’s clothing and potential handling of the condom without gloves by Lifecodes technician Palmer), the lack of female DNA in earlier nonsperm fraction testing making her question if a sex act occurred, and the assumptions underlying STRmix modeling. The expert agreed with prior testimony that the sperm fraction was a robust single-source profile matching Aguirre but opined the overall DNA evidence against Aguirre was weak.
On recall as a rebuttal witness, Heath explained environmental factors, including rain or mist, could have washed DNA off the exterior of the nonporous condom, while the porous paper of the evidence bag would have absorbed transferred DNA material. She concluded a sex act occurred based on ejaculate matching Aguirre that was present within the interior of the condom.
10
State v. Aguirre Procedural history By amended information, the State charged Aguirre with first degree premeditated murder or, in the alternative, second degree murder. Prior to trial, Aguirre moved to suppress the DNA evidence due to spoliation, lack of chain of custody and authenticity, and requested a Frye 8 hearing. In briefing, Aguirre documented the understood chain of custody for the condom and DNA extracts. The State in its response brief included a detailed timeline of chain of custody for the relevant items and produced documentary evidence in support of the timeline.
In the reply brief and at the hearing on Aguirre’s motion to suppress, counsel for Aguirre confirmed a Frye hearing was no longer requested and shifted the argument to a request to exclude evidence under ER 702. As to chain of custody, Aguirre’s counsel stated the parties were, “pretty much in agreement” on the chronology. VRP (Nov. 1, 2023) at 17. Oral argument focused on possible cross-contamination from Crime Lab technician Morig’s DNA, Lifecodes’s consumption of the condom during its testing, the failure of Lifecodes to maintain reagent blanks, the absence of female DNA in earlier testing contrasted with the later recovery of a DNA mixture that had trace amounts of Doss’s DNA, and the claim that the STRmix testing process and procedures were broken
8 Frye v. United States, 54 App. D.C. 46, 293 F. 1013 (1923).
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State v. Aguirre and unreliable. The defense argued that the evidence was contaminated, mishandled, misidentified, or cross-contaminated to such an extent that the results were unreliable and therefore unhelpful to the trier of fact.
The trial court issued an oral ruling that was later incorporated into its comprehensive written findings of fact and conclusions of law. The trial court ruled that the State had made a prima facie showing and any flaws or issues with chain of custody, procedures, contamination or cross-contamination, or biases went to the weight of the evidence, and found the State had made a prima facie showing as to chain of custody.
At trial, after the conclusion of testimony from Dr. Michael Baird and Lisa Bennett of Lifecodes, Aguirre renewed aspects of his evidentiary objections due to spoliation, contamination, and unreliability under ER 702. The trial court analyzed the issues under both Frye and ER 702, and ruled the DNA evidence resulted from generally accepted testing within the scientific community and that the challenges to the evidence went to its weight, not admissibility.
At the close of the State’s case-in-chief, Aguirre moved for dismissal based on insufficient evidence. The trial court denied the motion and the case proceeded with further testimony and closing arguments.
Approximately one week after the close of trial, the trial court held a hearing to announce its verdict and read from detailed findings of fact and conclusions of law the
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State v. Aguirre court had prepared. The court’s written findings of fact and conclusions of law were filed one month later. The trial court found the State proved beyond a reasonable doubt that Aguirre committed the murder of Doss, with a sequence of events including a sex act, a violent struggle in the straw of the manure pit, and pursuit of Doss by Aguirre of over 200 feet, during which she was struck in the head multiple times and strangled for no less than three minutes. The trial court concluded that Aguirre was guilty of first degree premeditated murder shown by circumstantial evidence of the initial altercation, the pursuit of over 200 feet, multiple blunt force strikes to the head, and strangulation of over three minutes. Aguirre was sentenced to 300 months of incarceration.
Aguirre timely appeals.
ANALYSIS
1. Admission of DNA evidence Aguirre argues the DNA evidence was “tainted at the outset” and “plagued by several foundational problems.” Br. of Appellant at 33. He challenges the admission of two related pieces of DNA evidence: (1) the sperm fraction profile developed from DNA extracts obtained from the condom collected in 1986, and (2) the low-level mixture of DNA recovered in 2017 from the interior of the paper evidence bag that initially contained the condom upon collection from the crime scene. He contends all DNA evidence should have been excluded for lack of proper chain of custody, authenticity
13
State v. Aguirre problems, and unreliability under ER 702. Aguirre focuses on contamination, loss of the physical condom, the decades-long interval before the evidence bag was tested, two people who had contact with the condom that did not testify, and an assertion that given all of these issues the probabilistic genotyping testing in 2017 and 2018 was necessarily unreliable.
A. Standard of review “The trial court is necessarily vested with a wide latitude of discretion in determining admissibility [of evidence], which will not be disturbed absent clear abuse.” State v. Campbell, 103 Wn.2d 1, 21, 691 P.2d 929 (1984).
Authentication or identification of an exhibit under ER 901 requires only a showing sufficient to support a finding that the item is what the proponent claims. “‘The bar for authentication of evidence is not particularly high.’” State v. Hillman, 24 Wn. App. 2d 185, 191, 519 P.3d 593 (2022) (quoting United States v. Gagliardi, 506 F.3d 140, 151 (2d Cir. 2007)). For physical evidence that is not readily identifiable, the State ordinarily establishes authenticity through chain of custody testimony to establish with sufficient completeness that it is improbable that the item was exchanged, contaminated, or tampered with. State v. Roche, 114 Wn. App. 424, 436, 59 P.3d 682 (2002) (citing United States v. Cardenas, 864 F.2d 1528, 1531 (10th Cir. 1989)). Biological evidence, such as the condom and related DNA, is susceptible to alteration
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State v. Aguirre and requires testimony on chain of custody. The proponent need not identify the item with absolute certainty or eliminate every possibility of alteration or substitution. Campbell, 103 Wn.2d at 21. Not every person who handled the item must testify. State v. Lui, 179 Wn.2d 457, 481, 315 P.3d 493 (2014) (abrogated on other grounds by Smith v. Arizona, 602 U.S. 779, 144 S. Ct. 1785, 219 L. Ed. 2d 420 (2024)). Authentication may be established through a combination of witness testimony, labels, initials, dates, seals, and secure handling procedures, so long as distinctive characteristics combined with other circumstances indicate the evidence is what the proponent claims it to be. State v. Payne, 117 Wn. App. 99, 106-07, 69 P.3d 889 (2003); Int’l Ultimate, Inc. v. St. Paul Fire & Marine Ins. Co., 122 Wn. App. 736, 746-47, 87 P.3d 774 (2004). Minor gaps or discrepancies affect weight, not admissibility. Campbell, 103 Wn.2d at 21. Speculative concerns about possible contamination do not preclude admission absent evidence that contamination was probable. State v. Boehme, 71 Wn.2d 621, 638, 430 P.2d 527 (1967), cert. denied, 390 U.S. 1013, 88 S. Ct. 1259, 20 L. Ed. 2d 164 (1968).
Expert testimony based on scientific evidence must satisfy both Frye and ER 702.
Lakey v. Puget Sound Energy, Inc., 176 Wn.2d 909, 918, 296 P.3d 860 (2013). Frye addresses whether the methodology is generally accepted in the scientific community; ER 702 addresses whether the expert applied a reliable method and whether the testimony will help the trier of fact. Id. A trial court’s ruling under Frye is reviewed
15
State v. Aguirre de novo. Anderson v. Akzo Nobel Coatings, Inc., 172 Wn.2d 593, 600, 260 P.3d 857 (2011). Aguirre did not raise a Frye challenge, so only ER 702 is at issue. Under ER 702, the court asks two questions: (1) whether the witness is qualified as an expert, and (2) whether the testimony will be helpful to the trier of fact. Unreliable testimony is generally regarded as unhelpful and therefore inadmissible. Erickson v. Pharmacia, LLC, 5 Wn.3d 585, 634-35, 578 P.3d 306 (2025). A trial court’s ER 702 ruling is reviewed for abuse of discretion. Lakey, 176 Wn.2d at 919 (citing State v. Yates, 161 Wn.2d 714, 762, 168 P.3d 359 (2007)). “Trial courts are given a large degree of freedom when making these determinations, subject to reversal only for a clear abuse of discretion.” State v. Arndt, 194 Wn.2d 784, 799, 453 P.3d 696 (2019).
B. The sperm-fraction profile from the condom DNA extracts The State adequately authenticated the DNA extracts and the resulting male profile. The condom was collected in 1986, secured as Item No. 17 with the Spokane Police Department, and later hand-delivered to Lifecodes. At Lifecodes, the analyst obtained the biological material from the condom and extracted the DNA focusing on the high molecular weight sperm fraction. The physical condom was discarded after the determination was made that all biological material was removed, which was a common practice at the time. Item No. 17, which was now the empty paper evidence bag, was returned to the Spokane Police Department and checked back into the property room,
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State v. Aguirre with Lifecodes retaining the DNA extracts. Later, the DNA extracts were sent to the Spokane Police Department, booked into evidence as Item No. 57, and sent to Bode for testing and subsequently tested by Orchid Cellmark. Each laboratory produced a complete male DNA profile consistent with the other, and were later matched to DNA from Aguirre. Photographs, laboratory records, and the consistency in the testing results across different laboratories were sufficient to identify the DNA extract as originating from the condom tested by Lifecodes.
Aguirre emphasizes the destruction by Lifecodes of the physical condom, the absence of testimony from two early handlers of this evidence (Morig and Palmer), and the discrepancy between the detectives’ observation of visible ejaculate in the condom during its collection at the crime scene and the Lifecode analyst’s later observation that no visible semen remained. None of these points require exclusion.
Although Aguirre asserts that loss or destruction of the physical condom by Lifecodes in 1989 rendered the chain of custody fatally flawed, and only a black and white photograph of a used condom was available to the defense and fact finder at trial, 9
9 Aguirre’s assertion about only a black and white photo being available is not accurate. The record includes a color photograph of the used condom, exhibit P-52, as well as color video footage of the crime scene in 1986 that includes a view of the condom, exhibit P-14 at 12 min., 30 sec. to 13 min., 12 sec.
17
State v. Aguirre the relevant biological material for later STR testing was the retained DNA extracts from the condom, not the discarded condom. Testimony about the collection of the condom, photographs, and the laboratories’ handling of the DNA extracts adequately identified the source.
The absence of testimony from two early handlers, who briefly came into contact with the condom (Crime Lab employee William Morig, whose DNA was later found on Doss’s clothing, and Lifecodes employee Regina Palmer, who logged Item No. 17 when it arrived at the laboratory) does not render the chain of custody so broken that admission should be disallowed. Concerns about potential contamination of the condom evidence remained speculative; Aguirre offered no actual evidence that contamination was probable. Boehme, 71 Wn.2d at 638. Subsequent testing of the sperm fraction by two separate laboratories produced a clean single-source male DNA profile matching Aguirre. The parties largely agreed on the chain of custody chronology in pretrial proceedings. Differences between the detectives’ observations of the condom and ejaculate during collection of evidence at the crime scene, and the Lifecode analyst’s subsequent observations of the condom are explained by the passage of time and the extraction process itself. Biological material dries and an analyst is looking for something different when conducting RFLP testing. Such differences go to weight, not admissibility.
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State v. Aguirre The trial court did not abuse its discretion in admitting into evidence the sperm-
fraction profile and related expert testimony.
C. The low-level mixture of DNA recovered from the evidence bag Aguirre’s stronger challenge targets the 2017 swabs from the interior of the original paper evidence bag that held the condom and the resulting data used in the 2017 and 2018 STRmix analysis of the low-level mixture of DNA. He argues unreliability because the bag was examined more than thirty years after collection, earlier testing of the DNA extracts detected no female DNA in the nonsperm fraction, and contamination risks existed.
The State established the evidence bag was the same bag that contained the condom. Lorraine Heath of the Crime Lab identified the bag by its markings, initials, dates, and seals. The State accounted for the condom and empty evidence bag through each step in the chain of custody with testimony that included witnesses identifying their personal signatures or initials, dates, and descriptions of the evidence’s condition.
For example, relative to chain of custody, Lorraine Heath testified:
. . . So starting with the exterior package, I can already recognize the item. It has the evidence bar code that is applied by the Spokane crime lab when it is received from the law enforcement agency. In addition—
excuse me, there is my initials and dates of when I examined this item.
On the exterior packaging, I documented the case number, the item number, and then the date and my initials. And you can also see evidence tape that
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State v. Aguirre
I applied after I examined the item and I resealed it, and that has my date and initials on it, too.
....
So inside the outer paper bag, there is a white envelope with a label on it. Again, you—I can see the date, initials, case number and item number on the outside of the packaging, indicating I examined it, and then the evidence seal, the blue tape that has my date and initials on it, indicating when I sealed it back up. And it’s open at the short end.
....
. . . So inside the white envelope, is another paper bag, a smaller paper bag, and it, too, has the case number, item number, and date and initials that I examined it. And it’s not sealed because it was the item I was actually examining.
3 VRP (Dec. 18, 2023) at 1206-07. Testimony similar to Heath’s regarding timing of receipt of evidence, documentation of initials and dates, sealing and securing of evidence, and subsequent conveyance of the evidence was proffered by each witness testifying at trial. The chain was sufficiently complete.
The absence of testimony from Morig and Palmer does not break the chain.
The suggestion that Morig’s DNA on Doss’s clothing somehow cross-contaminated the evidence bag remains speculative. Speculative contamination arguments do not establish a probability that the item was not what the State claimed. See Boehme, 71 Wn.2d at 638. Those arguments, therefore, go to weight.
Heath testified that her testing methodology and process were generally accepted in the scientific field. The defense expert agreed the type of testing and methodology
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State v. Aguirre were generally accepted, and instead raised challenges related to degradation and modeling assumptions. Disputes about the interpretation of the low-level DNA mixture or the statistical assumptions used go to weight once the technique itself was accepted.
The earlier absence of detectable female DNA in STR testing of the DNA extracts does not render the later probabilistic genotyping results unreliable. Differential extraction prioritized the sperm fraction. Epithelial cells (skin) can remain on packaging and become detectable only with more sensitive modern methods. Heath explained the scientific basis for the transfer of DNA from a nonporous condom surface to porous paper packaging and for a difference in DNA persistence on an item under environmental conditions. The trial court heard the competing explanations, including the defense theory of contamination linked to earlier laboratory handling, then noted the limitations and concluded the evidence was sufficiently reliable to be considered. The trial court expressly stated it would carefully weigh the evidence as fact finder.
STRmix is generally accepted in the scientific community. Experts for the State and defense testified to this. The trial court conducted a thorough pretrial hearing, found the State’s expert qualified, and found the methods validated. It recognized the limitations inherent in low-level, degraded, mixed samples of DNA recovered decades later from packaging when the original item in the packaging had been consumed in
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State v. Aguirre the absence of contemporaneous generated reagent blanks. Those limitations are real. Low-level DNA, degradation, transfer, and modeling assumptions can affect the reliability of a likelihood ratio. The defense expert contested the assumptions and the strength of the resulting ratio. The trial court, sitting as fact finder, heard both experts and was in the best position to evaluate the competing views.
Importantly, the STRmix result was never presented as standalone proof of identity or of the sex act. Instead, it was offered as corroborative of the already established sperm fraction match to Aguirre and the crime scene evidence. On this record, the application of STRmix was not so unreliable that the evidence failed to assist the trier of fact under ER 702. The trial court properly exercised its gatekeeping function.
D. Conclusion on admissibility; harmless error The State met its burden of authentication. The scientific methods were sufficiently reliable under ER 702. Remaining uncertainties—gaps in the chain of custody, destruction of the physical condom, the finding of female DNA on the packaging through probabilistic genotyping but not in STR testing of the DNA extracts, and possible contamination—were fully aired and properly treated as matters of weight. The trial court did not abuse its discretion in admitting the DNA evidence.
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State v. Aguirre Even if the low-level DNA mixture obtained from the evidence bag that once held the condom had been excluded, any error was harmless. 10 Aguirre alleges the trial court abused its discretion under ER 702. He is not claiming a constitutional error. Because the claimed error stems from an evidentiary ruling, we apply the nonconstitutional harmless error standard. State v. Gower, 179 Wn.2d 851, 854-55, 321 P.3d 1178 (2014). Under that standard, an erroneous admission of evidence is not prejudicial unless, within reasonable probabilities, the outcome of the trial would have been materially affected had the error not occurred. Barriga Figueroa v. Prieto Mariscal, 193 Wn.2d 404, 415, 441 P.3d 818 (2019). “‘The improper admission of evidence constitutes harmless error if the evidence is of minor significance in reference to the overall, overwhelming evidence as a whole.’”
10 The parties appeared for oral argument on December 1, 2025. The following day, this court directed supplemental briefing on a single question: “Assuming it was error for the trial court to admit evidence collected from the brown bag, described by the trial court as the ‘condom package,’ was the error harmless?” A staggered briefing schedule was set, with the State directed to file first, which it did. Aguirre moved to strike portions of the State’s supplemental brief, arguing the State was “rehashing arguments in support of the admissibility of the purported DNA mixture discovered on the brown bag.” Appellant’s Mot. to Strike at 3. He did not identify particular passages. Instead, he asked this court to strike “pages 3-20 of the Respondent’s Supplemental Brief” and “all portions of Respondent’s Supplemental Brief that are not directly pertinent to the issue of harmless error.” Appellant’s Mot. to Strike at 5. The motion is denied. We have considered only those arguments in the parties’ supplemental briefing responsive to the question we posed.
23
State v. Aguirre State v. Wasuge, 5 Wn.3d 877, 890, 582 P.3d 320 (2026) (quoting State v. Bourgeois, 133 Wn.2d 389, 403, 945 P.2d 1120 (1997).
Here, the sperm fraction profile matched Aguirre. That was independently admitted and powerful. That evidence, in combination with the evidence about the crime scene, the narrow time window in which the murder occurred, Aguirre’s statements, and the remaining evidence, overwhelmingly supported the finding of identity and sequence of events. The low-level DNA mixture evidence obtained from the paper evidence bag was cumulative. There is no reasonable probability that exclusion of that evidence would have materially affected the outcome of the trial. 2. Sufficiency of the evidence Aguirre challenges the sufficiency of the evidence. He first contends the trial court’s fact-finding process was skewed and that certain findings rested solely on speculation. He then claims the State presented insufficient evidence to prove identity or premeditation.
In State v. Roberts, 5 Wn.3d 222, 572 P.3d 1191 (2025), the Washington Supreme Court clarified the standard of review for challenges to sufficiency of evidence following a criminal bench trial. The purpose of a sufficiency of the evidence inquiry is to ensure that the fact finder rationally applied the constitutional standard of proof beyond a reasonable doubt as required by the due process clause of the Fourteenth Amendment to
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State v. Aguirre the United States Constitution. Id. at 231. The question is, after reviewing all of the evidence in the light most favorable to the prosecution, whether any rational trier of fact could have found the essential elements of the crime beyond a reasonable doubt. Id. (quoting Jackson v. Virginia, 443 U.S. 307, 318-19, 99 S. Ct. 2781, 61 L. Ed 2d 560 (1979)). 11 Written findings and conclusions that are required by CrR 6.1(d) “assist an appellate court’s review of the questions raised on appeal” and “facilitate appellate review,” but do not limit appellate review of all the evidence. Id. at 234. An appellate court’s review of all the evidence does not mean that the appellate court will reweigh evidence; deference is given to the trier of fact on issues of credibility, conflicting testimony, and persuasiveness. Id. at 234-35 (citing State v. Thomas, 150 Wn.2d 821, 874, 83 P.3d 970 (2004); State v. Killingsworth, 166 Wn. App. 283, 287, 269 P.3d 1064 (2012); Quinn v. Cherry Lane Auto Plaza, Inc., 153 Wn. App. 710, 717, 225 P.3d 266 (2009)). Challenges to a trial court’s conclusions of law are reviewed de novo. Id. at 237 (citing State v. Gatewood, 163 Wn.2d 534, 539, 182 P.3d 426 (2008)). A claim of insufficient evidence admits the truth of the State’s evidence and all reasonable inferences that can be drawn from it. State v. Salinas, 119 Wn.2d 192, 201, 829 P.2d
11 Washington adopted Jackson in State v. Green, 94 Wn.2d 216, 221, 616 P.2d 628 (1980) (plurality opinion).
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State v. Aguirre 1068 (1992). Circumstantial evidence is equally reliable as direct evidence when assessing the sufficiency of the evidence. State v. Delmarter, 94 Wn.2d 634, 638, 618 P.2d 99 (1980). Unchallenged findings of fact are verities on appeal. State v. O’Neill, 148 Wn.2d 564, 571, 62 P.3d 49 (2003).
A. The trial court’s fact finding process As an initial matter, Aguirre contends the trial court ignored evidence favorable to him (including the absence of his DNA on Doss’s clothing and the presence of an unknown male’s DNA on Doss’s underpants and blouse) and thereby demonstrated bias.
Washington’s appearance of fairness doctrine requires a judicial officer not only to be impartial but to appear impartial. State v. Gamble, 168 Wn.2d 161, 187, 225 P.3d 973 (2010). The test is objective: whether a reasonably prudent, disinterested person would conclude that the proceeding was fair, impartial, and neutral for all parties. Tatham v. Rogers, 170 Wn. App. 76, 96, 283 P.3d 583 (2012). The presumption is that a trial judge performs their job without prejudice or bias. West v. Wash. Ass’n of County Officials, 162 Wn. App. 120, 136, 252 P.3d 406 (2011). A challenging party must overcome this presumption with specific facts establishing bias. State v. Lester, __ Wn. App. 2d __, 589 P.3d 816, 820 (2026). Mere speculation is insufficient. State v. Chamberlin, 161 Wn. 2d 30, 37, 162 P.3d 389 (2007).
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State v. Aguirre Aguirre has not identified specific facts establishing bias. The trial court expressly considered evidence that another suspect may have committed the crime, and found the State proved Aguirre committed the murder. Disagreement with that determination does not establish an appearance of fairness violation.
B. Findings of fact 24a, 54, and 55 Aguirre claims that the trial court’s findings of fact 24a, 54, and 55 are based on speculation and conjecture.
Finding of fact 24a states that a freshly used condom was positioned just outside the manure pit consistent with the fact that Doss had purchased a single condom sometime around 9:30 p.m. on January 30, 1986. Detectives described the condom as “very fresh” with observable recent ejaculate. 1 (VRP) (Nov. 30, 2023) at 355. The adult bookstore employee told detectives that they sold Doss a condom between 9:00 p.m. and 9:30 p.m. on January 30. Multiple officers testified no other condoms were present at the crime scene and no condoms were found on Doss’s person. No more than 90 minutes elapsed between the purchase of the condom and the discovery of Doss’s body at 10:30 p.m. A rational fact finder could find beyond a reasonable doubt the purchased condom was the same one found at the crime scene.
Finding of fact 54 states that, given the narrow window of time and fresh condition of the condom containing Aguirre’s DNA, it was unlikely and not reasonable
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State v. Aguirre to assume that Aguirre had a different sexual encounter with a different individual, especially in light of the 8,100-to-1 ratio that it was his DNA and that of Ruby Doss versus his DNA and that of another individual. The narrow time frame and the description of the condom as “fresh” are supported by the record as already discussed. Lorraine Heath’s statistical testimony supplies the additional support for this finding. The trial court found Heath’s testimony credible. A rational trier of fact could determine it was unreasonable that Aguirre had a different sexual encounter with a different individual.
Finding of fact 55 states that Aguirre admitted to choking and hitting a woman and leaving her for dead within the same timeframe in which he was stationed in the Spokane area in January 1986. Aguirre asserts the statements he made lacked a specific location or particular date or time. However, his statements about hitting and choking a woman, combined with his presence in the Spokane area in January 1986, and the DNA evidence that link him to the crime scene, support a reasonable inference that his statements did relate to this offense. The trial court found the testimony of Aguirre’s friends, coworkers, and acquaintances to be credible. A rational trier of fact could find beyond a reasonable doubt that Aguirre’s statements related to Ruby Doss.
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State v. Aguirre C. Identity and pursuit Aguirre argues insufficient evidence supports the findings that he was the person who pursued Doss from the manure pit to the concrete bunker where she was ultimately discovered dead. He focuses on findings of fact 24.b, 28, 57, and 63, which all relate to Doss’s movement between the two locations. He contends the only credible evidence on movement and identity was from the defense shoe print expert who excluded him as having produced that print based on his foot size.
Although Aguirre in his briefing uses “lone suspect” in quotes in multiple instances, see Opening Br. of Appellant at 10, 27, 49, 50-51, that term does not appear anywhere in the trial court’s findings of fact and conclusions of law. Contrary to Aguirre’s assertions, unchallenged finding of fact 60 indicates that the trial court did consider all evidence on other proffered suspects and instead determined that the State proved Aguirre murdered Doss. “This finding is based upon [Aguirre’s] statements, the DNA, the circumstances surrounding the death, the timeframe involved, and the evidence.” CP at 1190.
As to the shoe print, the trial court agreed with Aguirre that it could not determine whether the shoe print was from Aguirre, Doss, or an unrelated individual. That finding does not, however, undermine the evidence admitted at trial that did link Aguirre to the crime scene.
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State v. Aguirre The sperm fraction DNA profile provides powerful evidence establishing that Aguirre had sexual contact with Doss at the crime scene in the narrow window of time between Doss’s purchase of the condom and discovery of her body. The identity of Aguirre as the killer rests on the cumulative force of the DNA evidence, the physical reconstruction of the crime scene, the narrow time window involved, and the context garnered from Aguirre’s statements about having sex with Doss and having hit and choked a woman which is consistent with Doss’s injuries. The condom was described as “fresh” and found near the manure pit where Doss’s personal items, including a crumpled $50 bill, were recovered. Doss purchased a condom between 9:00 p.m. and 9:00 p.m.; her body was discovered around 10:30 p.m. No other condoms were found on Doss’s person or anywhere at the crime scene. The physical evidence supports a reasonable inference that Doss struggled in the manure pit with the person who left the condom and then moved to the location where her body was found.
Aguirre’s statements made to others: “‘I fucked the bitch, but I didn’t kill her,’”
2 VRP (Dec. 6, 2023) at 624, and “‘she was alive when I left,’” 2 VRP (Dec. 7, 2023) at 705, are consistent with sexual contact with Doss although those statements come with the assertion that she was alive when he left. These statements are not explicit confessions to the murder. However, the match of Aguirre’s DNA to the condom renders his statement about sexual contact with Doss highly credible. The accompanying
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State v. Aguirre references to violence against a woman, made in the context of discussions about this particular case or this particular victim, support the further inference that he was describing this incident rather than some unrelated event.
Viewed in the light most favorable to the State, a rational fact finder could find beyond a reasonable doubt that Aguirre was the perpetrator.
D. Premeditation Aguirre next argues insufficient evidence supports the trial court’s finding of premeditation. He contends the trial court incorrectly relied on unsupported findings that he pursued Doss for over 200 feet and on the amount of time required to strangle her.
To convict a defendant of first degree premeditated murder, the State must prove that the defendant acted with “premeditated intent to cause the death of another person.” RCW 9A.32.030(1)(a). “[P]remeditation is a separate and additional element to the intent requirement for first degree murder.” State v. Bingham, 105 Wn.2d 820, 827, 719 P.2d 109 (1986). A defendant may act with intent to kill but without premeditation. State v. Ollens, 107 Wn.2d 848, 851-52, 733 P.2d 984 (1987). Premeditation may be proved by circumstantial evidence where the inferences are reasonable and the supporting evidence substantial. State v. Pirtle, 127 Wn.2d 628, 643, 904 P.2d 245 (1995) (citing State v. Gentry, 125 Wn.2d 570, 597, 888 P.2d 1105 (1995)). It requires more than a moment in time; it is defined as “‘the deliberate formation of and reflection upon the intent to take a
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State v. Aguirre human life and involves the mental process of thinking beforehand, deliberation, reflection, weighing or reasoning for a period of time, however short.’” State v. Castro DeJesus, 7 Wn. App. 2d 849, 883, 436 P.3d 834 (2019) (quoting State v. Hoffman, 116 Wn.2d 51, 82-83, 804 P.2d 577 (1991)). Examples of evidence supporting a finding of premeditation include: motive, prior threats, multiple wounds inflicted or multiple shots, striking the victim from behind, generally the manner or method of killing, assault with numerous means or a weapon not readily available, and the planned presence of a weapon at the scene. Hoffman, 116 Wn.2d at 83; Bingham, 105 Wn.2d at 827; State v. Rehak, 67 Wn. App. 157, 164, 834 P.2d 651 (1992).
Here, the evidence supports a reasonable inference of a sequence of events rather than a single continuous impulsive assault. The initial struggle occurred in the manure pit where Doss’s personal items and the fresh condom were later found. Her body was located more than 200 feet away. The autopsy of Doss revealed that she had been struck multiple times in the head and subjected to sustained pressure with sufficient force to fracture the hyoid bone and cause her death. The distance of approximately 250 feet between the place where the struggle began to where Doss’s the body was discovered, combined with the use of two distinct methods of attack upon Doss, supplies ample evidence of reflection. This is not a case in which the State solely relied upon the time required to complete strangulation.
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State v. Aguirre Viewing the evidence in the light most favorable to the State, a rational trier of fact could find premeditation beyond a reasonable doubt. Accordingly, we hold the State presented sufficient evidence of premeditation to support Aguirre’s first degree murder conviction.
CONCLUSION
The trial court did not abuse its discretion in admitting the DNA evidence.
Even if the low-level DNA mixture obtained from the paper evidence bag that originally contained the condom had been excluded, any error would have been harmless. Sufficient evidence supports the conviction for premeditated first degree murder. The judgment and sentence are affirmed.
A majority of the panel has determined this opinion will not be printed in the Washington Appellate Reports, but it will be filed for public record pursuant to RCW 2.06.040.
Murphy, J.
WE CONCUR:
Staab, C.J. Lawrence-Berrey, J.