Affirmed and Opinion Filed August 24, 2022
S In The Court of Appeals Fifth District of Texas at Dallas No. 05-21-00534-CR
LAXAVIER LAMAR WHITTLEY, Appellant V. THE STATE OF TEXAS, Appellee
On Appeal from the 417th Judicial District Court Collin County, Texas Trial Court Cause No. 417-81486-2020
MEMORANDUM OPINION Before Justices Partida-Kipness, Pedersen, III, and Nowell Opinion by Justice Partida-Kipness Appellant Laxavier Lamar Whittley appeals his conviction for aggravated
sexual assault. In two issues, Whittley challenges the sufficiency of the evidence to
support the jury’s guilty verdict and the admission of expert testimony from forensic
DNA analyst Cassandra Canela. We overrule Whittley’s issues and affirm the
judgment. BACKGROUND
Around 5:30 a.m. on July 8, 2019, sixty-one-year-old P.B.1 awoke when she
felt something brush against her leg in bed. Her husband had already left for the day,
and her two adult daughters were sleeping in their rooms. P.B. sat up and saw the
silhouette of a man with a gun at the foot of the bed. P.B. described him as “just a
total black silhouette.” She told the jury he was wearing “all black” and what looked
like a black jacket.
P.B. “was scared” when she saw the attacker had a gun and begged him not
to hurt her. The attacker told her to “hush, be quiet” and instructed her to lie face
down “crossways on the bed.” She did so and, “within a matter of seconds,” P.B.
“felt a sharp, rough object stuck into” her vagina that seemed “like a glove or
something.” P.B. told the jury the attacker then stuck “rough objects into [her] rear-
end.” P.B. assumed the objects were the gun, his gloved hand, and his penis. P.B.
recalled this “was horribly painful,” and she “was just begging him to stop hurting
[her].” She avoided looking at the attacker because she thought that was her “best
chance of survival.” P.B. tried to defend herself by grabbing a lamp and swinging it
at him, but the lamp was “so cumbersome” the attack did not work. At some point,
the attacker asked whether she had any cash in the house. P.B. told him she did not
keep cash, but he could take her purse, which was downstairs.
1 We refer to the complainant, P.B., by initials to protect her identity. See TEX. R. APP. P. 9.8(a).
–2– As the assault continued, the attacker “came up beside [her] and demanded
oral sex.” P.B. complied. When her alarm went off around 6:30 a.m., P.B. told the
attacker it was “getting light outside” and her “neighbors leave early for work.” P.B.
told the jury she was “hoping he would realize, you know, I probably need to escape,
it’s not dark anymore.” The attacker did not immediately leave. Instead, he got up,
moved behind P.B., and began rubbing his penis on her back. P.B. felt wetness on
her back and believed it to be semen.
P.B. testified that when the attacker finished, he told her to “stay there, lay
down, and pull the covers over your head.” P.B. “laid there quietly” and “just
listened.” She was worried the attacker would go after her daughters next. “After a
few minutes [P.B.] realized that he probably had left” because she had not heard her
daughters’ voices. At that point, P.B. ran to her younger daughter’s bedroom and
asked her to call 911.
P.B. testified she could tell the attacker was African American from the color
of his penis. In her written statement to police, P.M. said the attacker “sounded
black” but did not say she was able to determine the color of his skin. P.B. was taken
to the hospital and treated by Stephanie Barnes, a sexual assault nurse examiner.
Barnes testified P.B. had bruising in her vaginal area and tears and bruising in her
anal area so severe Barnes called the emergency room to see if P.B. required sutures.
Barnes collected DNA swabs of the areas where the attacker had reportedly touched
P.B.: orally, anally, vaginally, and on her back.
–3– There is an alleyway behind P.B.’s home that leads to a nearby apartment
complex. Police found a bandana stuffed inside a glove and a footprint on top of a
trashcan in the alleyway. Police theorized the attacker had used the trashcan to climb
over a wall between P.B.’s house and the apartment complex. Surveillance video
from the home showed the attacker had short hair and was wearing black clothing
and red, checkered Vans shoes.
A security officer at the adjacent apartments referred police to an “apartment
of interest.” Through interviews, authorities learned Jaevon Murphy lived in the
apartment of interest and Whittley was living with Murphy and sleeping on his
couch. Police took DNA swabs from both men along with two other suspects
associated with the apartment. While searching the apartment, police found a single
black glove in the bedroom closet and a handgun with red stains on the barrel hidden
inside an ottoman near the couch where Whittley slept. Police also discovered
Murphy owned a pair of red, checkered Vans shoes. However, Murphy had long
dreadlocks, which did not match the surveillance images of the short-haired attacker.
DNA testing shed further light on the attacker’s identity. The DNA evidence linked
Whittley to the offense and excluded the other suspects.
Whittley was sixteen years old at the time of the offense. The trial court
certified and tried him as an adult. The jury found Whittley committed aggravated
sexual assault and assessed punishment at fifty-five years. The trial court rendered
judgment on the verdict. This appeal followed.
–4– STANDARD OF REVIEW
In a sufficiency review, we view all the evidence in the light most favorable
to the verdict to determine whether any rational factfinder could have found the
crime’s essential elements beyond a reasonable doubt. Jackson v. Virginia, 443 U.S.
307, 319 (1979); Queeman v. State, 520 S.W.3d 616, 622 (Tex. Crim. App. 2017).
We may not reevaluate the evidence’s weight and credibility or substitute our
judgment for the factfinder’s. Queeman, 520 S.W.3d at 622. Instead, we determine
whether the necessary inferences are reasonable based on the cumulative force of
the evidence when viewed in the light most favorable to the verdict. Murray v. State,
457 S.W.3d 446, 448 (Tex. Crim. App. 2015). We presume the factfinder resolved
any conflicting inferences in favor of the verdict, and we defer to that resolution. Id.
at 448–49.
A trial judge’s ruling on the admissibility of expert testimony is reviewed for
an abuse of discretion and will not be disturbed if it is within the zone of reasonable
disagreement. Wolfe v. State, 509 S.W.3d 325, 335 (Tex. Crim. App. 2017). In
sorting untested or invalid theories from those grounded in “good” science, trial
judges are called upon to serve as gatekeepers. Id. at 336. The trial court’s essential
gatekeeping role is to ensure evidence lacking a basis in sound scientific methods is
not admitted. Id. “The court in discharging its duty as gatekeeper must determine
how the reliability of particular testimony is to be assessed.” Vela v. State, 209
–5– S.W.3d 128, 134 (Tex. Crim. App. 2006). “The reliability inquiry is, thus, a flexible
one.” Id.
ANALYSIS
Whittley brings two issues on appeal. First, he maintains the evidence was
legally insufficient to support the conviction. Second, he asserts the trial court erred
by admitting the expert testimony of a forensic DNA analyst. We will address each
issue in turn.
I. Sufficiency of the Evidence
At trial, Whittley did not dispute whether a sexual assault occurred, only
whether he was the one who committed the crime. He takes the same approach in
his first issue on appeal. Whittley notes P.B. was unable to identify the man who
assaulted her. He maintains the other evidence connecting him to the crime
amounted to no more than speculation and fell short of the standard required to
sustain a conviction. We disagree. The State’s DNA evidence, when paired with
other circumstantial evidence of guilt, was sufficient to prove Whittley’s identity as
the attacker.
The State is required to prove beyond a reasonable doubt the accused is the
person who committed the crime charged. Johnson v. State, 673 S.W.2d 190, 196
(Tex. Crim. App. 1984). Identity may be proved by either direct or circumstantial
evidence coupled with all reasonable inferences from the evidence. Gardner v. State,
306 S.W.3d 274, 285 (Tex. Crim. App. 2009). “Eyewitness identification is not
–6– required, and DNA evidence alone may establish an attacker’s identity in a rape
prosecution.” Molina v. State, 587 S.W.3d 100, 109 (Tex. App.—Houston [1st Dist.]
2019), aff’d, 632 S.W.3d 539 (Tex. Crim. App. 2021); accord Coria-Gonzalez v.
State, No. 03-18-00645-CR, 2020 WL 465856, at *4 (Tex. App.—Austin Jan. 29,
2020, no pet.) (mem. op., not designated for publication) (collecting cases); Allen v.
State, Nos. 05-11-00056-CR, 05-11-00057-CR, 2012 WL 2106530, at *2 (Tex.
App.—Dallas June 12, 2012, pet. ref’d) (not designated for publication).
Multiple DNA samples were taken from P.B.’s person and from objects
associated with the offense. At the hospital, Barnes collected swabs from the places
P.B. reported the attacker had touched her: her mouth, genitals, anus, and back.
Presumptive testing showed blood was present on the barrel of the handgun found
hidden in the apartment where Whittley was staying, so lab technicians took swabs
of the weapon’s grip, trigger, and release. They also swabbed the glove and bandana
found in the alleyway where police believed the attacker fled the scene.
Testing showed male DNA was present on P.B.’s anal, vaginal, and back
swabs, though the oral swab was inconclusive. Y-STR DNA testing of the back
swabs found two distinct DNA profiles matching P.B. and Whittley. According to
the State’s DNA expert, Cassandra Canales, tests showed it was 196 septillion times
more likely the DNA came from P.B. and Whittley than from P.B. and one unrelated,
unknown individual. Whittley could not be excluded as the contributor of the male
–7– DNA on the vaginal and anal swabs, though all the other suspects were excluded as
contributors there.
Testing of the swabs from the handgun’s grip, trigger, and release revealed
three DNA profiles, with P.B. as the most likely contributor of 93% of the DNA
present. Canales testified it was 3.74 decillion times more likely the DNA on the
handgun came from P.B., Whittley, and an unknown individual than from P.B. and
two unknown, unrelated individuals. Those test results were inconclusive as to
Murphy but excluded the other suspects as possible contributors.
Testing of the blood DNA found on the barrel of the gun suggested it was 14.6
septillion times more likely the blood DNA came from P.B. than an unrelated,
unknown individual. Testing of the glove showed four DNA profiles present inside.
P.B. was found to be 415 quintillion times more likely to have contributed a majority
of the glove DNA than unknown individuals, and the probability Whittley
contributed 21% of the remaining DNA was 39.6 million times greater than the
probability of it coming from unknown individuals. Together, the probability P.B.
and Whittley were the sources of most of the DNA inside the glove was 237 nonillion
times greater than the probability of obtaining this profile from unrelated, unknown
individuals. The other suspects, including Murphy, were excluded as possible
contributors to the DNA found in the glove.
The Texas Court of Criminal Appeals has described DNA forensics narrowing
the odds of a random match to one in 19,900,000 (an eight-digit number) as
–8– “impressive statistics” that “support[ed] the jury’s conclusion that appellant, as
opposed to some unidentified ‘suspect’ also sharing the same DNA profile, sexually
assaulted” the victim, when those statistics were paired with other circumstantial
evidence indicating guilt. Hinojosa v. State, 4 S.W.3d 240, 245 (Tex. Crim. App.
1999); see Guo v. State, No. 05-19-01178-CR, 2022 WL 224815, at *5 (Tex. App.—
Dallas Jan. 26, 2022, pet. ref’d) (mem. op., not designated for publication) (similar).
We conclude the forensic data in this case, some of which placed the odds at one to
a thirty-four-digit number, is also sufficient to support the verdict when paired with
the other circumstantial evidence linking Whittley to the crime.
Other circumstantial evidence tied Whittley to the crime in a variety of ways.
The apartment complex where Whittley lived was adjacent to P.B.’s house, and his
regular presence in the vicinity would have provided an opportunity to commit the
crime. See Mason v. State, 416 S.W.3d 720, 732 (Tex. App.—Houston [14th Dist.]
2013, pet. ref’d). Opportunity alone is generally not sufficient to prove identity, but
it is nonetheless a “circumstance[] indicative of guilt,” and thus identity. Temple v.
State, 390 S.W.3d 341, 360 (Tex. Crim. App. 2013); Merritt v. State, 368 S.W.3d
516, 526 (Tex. Crim. App. 2012). One black glove was found in the alleyway leading
from the house to the apartments, and another black glove was found in the
apartment where Whittley was staying. P.B. described her attacker as an African
American wearing all black wielding a handgun. Whittley is African American, and
the police found clothing of similar description and a handgun smeared with P.B.’s
–9– blood stuffed inside an ottoman in the apartment in which Whittley was living at the
time. The fact the complainant’s blood was found on a weapon associated with the
crime and hidden in the furniture near where Whittley slept speaks volumes as to
identity. See, e.g., Terry v. State, No. 05-08-00165-CR, 2009 WL 1240132, at *2
(Tex. App.—Dallas May 7, 2009, pet. ref’d, untimely filed) (not designated for
publication) (holding victim’s blood found on defendant’s articles to be persuasive
evidence of identity). Finally, as a resident of Murphy’s apartment, Whittley had
access to Murphy’s pair of distinctive, red-checkered Vans shoes, which were
identical to the ones the attacker wore on the surveillance video. See Castellon v.
State, 302 S.W.3d 568, 576 (Tex. App.—Amarillo 2009, no pet.) (mem. op.) (color
of shoes used to prove identity); cf. Segundo v. State, 270 S.W.3d 79, 88 (Tex. Crim.
App. 2008) (discussing “‘the mark of Zorro’ mode of proving identity” in which a
single “unusual fact” points strongly to the defendant).
“Proof of identity by circumstantial evidence is not subject to a more rigorous
review than proof by direct evidence, since both are equally probative.” Castellon,
302 S.W.3d at 575; accord Zavala v. State, No. 05-02-01773-CR, 2004 WL 625626,
at *2 (Tex. App.—Dallas Mar. 30, 2004, no pet.) (mem. op., not designated for
publication). Here, the circumstantial evidence is sufficient to prove Whittley’s
identity as the man who attacked P.B. We overrule his first issue.
–10– II. Admissibility of Expert Testimony
In his second issue, Whittley contests the admission of expert testimony
concerning Y-STR DNA tests connecting him to the crime. The State sponsored the
DNA evidence through Canela. Whittley challenges Canela’s qualifications. He also
disputes the reliability of the software Canela used to conduct Y-STR testing, a
program called STRmix.
The Texas Rules of Evidence set out three separate conditions before expert
testimony can be admitted: the witness qualifies as an expert by reason of his
knowledge, skill, experience, training, or education; the subject matter of the
testimony is an appropriate one for expert testimony; and admitting the expert
testimony will actually assist the factfinder in deciding the case. Rhomer v. State,
569 S.W.3d 664, 669 (Tex. Crim. App. 2019) (quoting Vela, 209 S.W.3d at 131).
These conditions are commonly referred to as qualification, reliability, and
relevance. Id. “The three requirements raise distinct questions and issues, and an
objection based on one of these requirements does not preserve error as to another.”
Shaw v. State, 329 S.W.3d 645, 655 (Tex. App.—Houston [14th Dist.] 2010, pet.
ref’d); accord Procella v. State, Nos. 05-11-01290-CR, 05-11-01291-CR, 2013 WL
222274, at *2 (Tex. App.—Dallas Jan. 17, 2013, no pet.) (not designated for
publication). Whittley did not object to Canela’s qualifications in the trial court. His
challenge to her qualifications is, therefore, not preserved for our review. See TEX.
R. APP. P. 33.1(a).
–11– Whittley objected to Canela’s testimony only on the ground that the
technology was unreliable. He reasserts that challenge here. The Kelly test for
reliability of evidence derived from a scientific theory requires the offering party
prove the following: (1) the underlying scientific theory must be valid, (2) the
technique applying the theory must be valid, and (3) the technique must have been
properly applied on the occasion in question. Wells v. State, 611 S.W.3d 396, 426
(Tex. Crim. App. 2020) (citing Kelly v. State, 824 S.W.2d 568, 573 (Tex. Crim. App.
1992)). To aid its determination of reliability under Kelly, the trial court may refer
to seven nonexclusive factors: (1) the extent to which the underlying scientific theory
and technique are accepted as valid by the relevant scientific community; (2) the
qualifications of any expert testifying; (3) the existence of literature supporting or
rejecting the underlying scientific theory and technique; (4) the potential rate of error
of the technique; (5) the availability of other experts to test and to evaluate the
technique; (6) the clarity with which the underlying scientific theory and technique
can be explained to the court; and (7) the experience and skill of any person who
applied the technique on the occasion in question. Kelly, 824 S.W.2d at 573.
“[R]eliability depends upon whether the evidence has its basis in sound scientific
methodology. This demands a certain technical showing.” Vela, 209 S.W.3d at 133
(quoting Jordan v. State, 928 S.W.2d 550, 555 (Tex. Crim. App. 1996)). That
showing gives a trial judge the opportunity to weed out testimony pertaining to so-
called “junk science.” Id. (quoting Jordan, 928 S.W.2d at 555). “The trial court’s
–12– gatekeeping function under Rule 702 does not supplant cross-examination as ‘the
traditional and appropriate means of attacking shaky but admissible evidence.’”
Wolfe, 509 S.W.3d at 336 (quoting Gammill v. Jack Williams Chevrolet, Inc., 972
S.W.2d 713, 728 (Tex. 1998)).
Canela has a bachelor’s degree in chemistry and a master’s degree in forensic
science. She had worked for the Texas Department of Public Safety’s Crime
Laboratory in Garland, Texas, for over six years at the time of trial. At trial, Canela
provided an overview of forensic genetics and her lab’s multistep process for
analyzing DNA. According to Canela, she begins a DNA analysis in a case involving
sexual assault with an initial screening using chemical reagents to detect the presence
of semen and male DNA. This initial screening helps to determine whether the
sample is a suitable candidate for Y-STR testing, which is designed to analyze male
DNA on the Y-chromosome. Criteria for suitability include the quantity of DNA as
well as its level of contamination. Canela then extracts the DNA from the subject
material and quantifies it.
Canela explained the next step is amplification, in which an enzymatic
“polymerase chain reaction” process was used to make billions of copies of the most
salient segments of DNA to facilitate their analysis while tagging the segments to
allow for better identification. Canela described how, at the fourth step, she feeds
the separated and amplified DNA strands into the STRmix machine. The machine
then analyzes the DNA and generates an output file, which Canela uses to interpret
–13– as a DNA profile. She next determines whether the profile is partial or full and how
many people contributed to the DNA profile by evaluating whether the data
coalesced around discernable “peak height” values for certain alleles, while
accounting for and guarding against the effects of statistical noise and sample
degradation. During this step, she also makes comparisons to any known DNA
profiles submitted for analysis.
From these measurements, the analyst and the STRmix software generates a
comparative statistic called a likelihood ratio, which Canela described as “a
mathematical relationship from two competing [hypotheses] which explains . . .
which hypothesis best describes the data.” The comparative statistic is calculated in
part through reference to probabilities derived from a national genetic statistics
database. She then verifies the results using her training and experience.
Canela told the jury the STRmix is used “in other laboratories across the
country” and “worldwide.” She also explained the software’s reliability had been
vetted through testing on two levels: through generalized, universally applicable
testing by the software developers and scientists, and by individualized validation at
each laboratory where the software was implemented, including the Garland crime
lab where Canela worked. At the Garland lab, the validation process consisted of
running DNA samples with known contributors in set ratios through the software,
with mixtures ranging from one to four contributors and with different
concentrations meant to mimic the real conditions under which tests would be
–14– conducted. Testers at the Garland lab had repeatedly run these samples through all
the machines in the lab to ensure they returned similar likelihood ratios and to
guarantee the results were reproducible. The testers then verified the software was
accurately separating the mixtures into their individual components. According to
Canela, through the Garland lab’s validation process, the system was tuned to
account for the quirks of the other lab instruments used in processing DNA. Separate
studies were run on each aspect of STRmix in a process that took “months.” Canela
further testified the lab had used the system reliably in the four years since it was
implemented in 2017. And Canela agreed she followed all lab-required and field-
approved procedures when testing the samples in this case.
Canela also offered testimony corresponding with the Kelly factors. She
testified STRmix is considered reliable in her field, it is a generally accepted tool in
her scientific community, and it will help the jury in understanding the DNA in this
case. According to Canela, the scientific theory underlying STRmix is the Markov
Chain Monte Carlo method, which is a widely accepted mathematical modeling
technique used in many disciplines, such as code breaking, physics, social science,
and computer linguistics. We conclude Canela’s testimony sufficiently established
the reliability of STRmix.
Moreover, DNA testing in general as well as Y-STR testing have been found
reliable and to have a sound scientific foundation. E.g. Jessop v. State, 368 S.W.3d
653, 671 (Tex. App.—Austin 2012, no pet.) (“DNA evidence has certainly been held
–15– admissible in Texas.”); see also Curtis v. State, 205 S.W.3d 656, 661 (Tex. App.—
Fort Worth 2006, pet. ref’d) (upholding determination that “Y[-]STR evidence was
reliable”); People v. Zapata, 2014 IL App (2d) 120825, ¶ 16, 8 N.E.3d 1188, 1194
(Y-STR testing reliable). The acceptance of a scientific theory by other courts is a
relevant consideration in assessing a trial judge’s ruling on questions of reliability.
Wolfe, 509 S.W.3d at 337. “When evaluating a trial judge’s gatekeeping decision,
appellate courts may take judicial notice of other appellate opinions concerning a
specific scientific theory or technique.” Somers v. State, 368 S.W.3d 528, 536–37
(Tex. Crim. App. 2012); see Morris v. State, 361 S.W.3d 649, 655 (Tex. Crim. App.
2011).
Regarding the STRmix software in particular, we take judicial notice of the
many opinions from other jurisdictions holding the software satisfies the state and
federal equivalents of Texas Rule of Evidence 702. See United States v. Gissantaner,
990 F.3d 457, 465–67 (6th Cir. 2021) (collecting cases and concluding STRmix
satisfies federal rule of evidence 702 and is the “product of reliable principles and
methods”); see also United States v. Christensen, No. 17-CR-20037-JES-JEH, 2019
WL 651500, at *2 (C.D. Ill. Feb. 15, 2019) (denying motion to exclude DNA results
on reliability ground and concluding STRmix met reliability standards); United
States v. Russell, No. CR-14-2563 MCA, 2018 WL 7286831, at *8 (D.N.M. Jan. 10,
2018) (holding STRmix met reliability requirements). Such decisions document
various peer-reviewed studies validating the software and its low rate of error. See,
–16– e.g., Gissantaner, 990 F.3d at 465 (“When examining ‘false inclusions,’ one peer-
reviewed study concluded, based on an analysis of the DNA of 300,000 people who
were known not to be in a mixture, that STRmix had accurately excluded the non-
contributors 99.1% of the time,” and observing the software gave low-confidence
estimates in cases of false inclusion); United States v. Lewis, 442 F. Supp. 3d 1122,
1128–29 (D. Min. 2020) (relying on a government study compiling data from thirty-
one laboratories, which “show[s] persuasively that STRmix is capable of producing
accurate results with extremely low error rates: STRmix not only works, it seems to
work extremely well, at least when used in the manner it was used in these studies”);
United States v. Washington, No. 8:19CR299, 2020 WL 3265142, at *3 (D. Neb.
June 16, 2020) (relying on same government study and citing Lewis); United States
v. Pettway, No. 12-CR-103S, 2016 WL 6134493, at *2 (W.D.N.Y. 2016) (overruling
Daubert objection to STRmix based in part on testimony “STRmix and its
underlying principles have been peer-reviewed in more than 90 articles”). Courts
have also noted the method used by STRmix is reliable because “there are
internal . . . validation checks” to ensure reliable application. See, e.g., State v.
Hudson, No. 1809009750, 2021 WL 4851971, at *5 (Del. Super. Ct. Oct. 15, 2021);
Lewis, 442 F. Supp. 3d at 1129.
Further, STRmix software has achieved general acceptance through its use “in
several federal laboratories, in more than forty states, and in at least thirteen other
countries.” Washington, 2020 WL 3265142, at *4. “At this point, STRmix is the
–17– market leader in probabilistic genotyping software.” Gissantaner, 990 F.3d at 466
(internal quotation marks omitted). “Consistent with this reality, numerous courts
have admitted STRmix over challenges to its general acceptance in the relevant
scientific community.” Id. (collecting cases). To our knowledge, only one federal
court has wholly rejected STRmix on reliability grounds, but the decision was later
reversed by the Sixth Circuit, which held STRmix satisfied the mandate of Daubert.
See United States v. Gissantaner, 417 F. Supp. 3d 857, 885 (W.D. Mich. 2019),
rev’d, 990 F.3d 457 (6th Cir. 2021). In short, “the STRmix method has been
subjected to extensive empirical testing and found to be accurate and reliable by the
FBI and numerous forensic laboratories.” People v. Davis, 290 Cal. Rptr. 3d 661,
680 (Cal. App. 2022). We reach the same conclusion here.
Finally, we conclude the underlying scientific theory and technique can be
clearly explained to the court. Canela’s testimony was clear and direct. Further, the
principles on which the software depends are well established and noncontroversial.
See Lewis, 442 F. Supp. 3d at 1135–65 (offering an exhaustive evaluation of
STRmix’s inner workings); see also People v. Bullard-Daniel, 42 N.Y.S.3d 714, 721
(N.Y. Co. Ct. 2016) (“[T]he mathematical models [behind STRmix] are themselves
non-controversial and have been widely used in fields such as weather forecasting,
computational biology, linguistics, genetics, engineering, physics, aeronautics,
finance, and social sciences.”). STRmix’s creator explained these principles in a
Michigan proceeding as follows:
–18– So if I split the construction of the software into having two fundamental principles, the mathematical principles and the molecular biology principles, the mathematical principles are standard mathematical principles and they date back to the early 1900s. And they’re called [Markov Chain Monte Carlo] and they’re a dominant method now in mathematical procedures treating these types of problems. If we come to the molecular biology these are based on empirical studies of the variability of peak and stutter heights in different multiplexes and at different template levels and they’re published in peer-reviewed articles.
People v. Muhammad, 931 N.W.2d 20, 30 (Mich. App. 2018). Indeed, as the court
in Lewis noted, the software has few drawbacks and many strengths, including its
compliance with three sets of international standards for probabilistic genotyping
software. See 442 F. Supp. 3d at 1150–51.
Overall, the case for reliability was compelling here. Canela’s testimony laid
a thorough reliability predicate, explaining each step in the STRmix process, their
scientific underpinnings, and the principles and protocols that kept the process in
line. Through judicial notice, this predicate is reinforced by the many courts across
the country that have assessed STRmix and found it trustworthy. Taking all this into
account, we cannot say the trial court abused its discretion by overruling Whittley’s
rule 702 objection and admitting testimony concerning STRmix. We overrule
Whittley’s second issue.
CONCLUSION
Under this record, we conclude the evidence was sufficient to support the
conviction and the trial court did not abuse its discretion by admitting Canela’s
–19– testimony. Accordingly, we overrule Whittley’s appellate issues and affirm the trial
court’s judgment.
/Robbie Partida-Kipness/ ROBBIE PARTIDA-KIPNESS JUSTICE
Do Not Publish. TEX. R. APP. P. 47.2(b). 210534F.U05
–20– S Court of Appeals Fifth District of Texas at Dallas JUDGMENT
LAXAVIER LAMAR WHITTLEY, On Appeal from the 417th Judicial Appellant District Court, Collin County, Texas Trial Court Cause No. 417-81486- No. 05-21-00534-CR V. 2020. Opinion delivered by Justice Partida- THE STATE OF TEXAS, Appellee Kipness. Justices Pedersen, III and Nowell participating.
Based on the Court’s opinion of this date, the judgment of the trial court is AFFIRMED.
Judgment entered this 24th day of August, 2022.
–21–