State v. K. Mullendore

2025 MT 282
CourtMontana Supreme Court
DecidedDecember 9, 2025
DocketDA 23-0169
StatusPublished

This text of 2025 MT 282 (State v. K. Mullendore) is published on Counsel Stack Legal Research, covering Montana Supreme Court primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
State v. K. Mullendore, 2025 MT 282 (Mo. 2025).

Opinion

12/09/2025

DA 23-0169 Case Number: DA 23-0169

IN THE SUPREME COURT OF THE STATE OF MONTANA

2025 MT 282

STATE OF MONTANA,

Plaintiff and Appellee,

v.

KAYLEA L. MULLENDORE,

Defendant and Appellant.

APPEAL FROM: District Court of the Thirteenth Judicial District, In and For the County of Yellowstone, Cause No. DC 20-1202 Honorable Colette B. Davies, Presiding Judge

COUNSEL OF RECORD:

For Appellant:

Carolyn Gibadlo, Attorney at Law, Missoula, Montana

For Appellee:

Austin Knudsen, Montana Attorney General, Christine Hutchison, Assistant Attorney General, Helena, Montana

Scott D. Twito, Yellowstone County Attorney, Victoria Callender, Amanda Tiernan, Deputy County Attorneys, Billings, Montana

Submitted on Briefs: October 8, 2025

Decided: December 9, 2025

Filed:

__________________________________________ Clerk Justice Laurie McKinnon delivered the Opinion of the Court.

¶1 Appellant Kaylea L. Mullendore (“Mullendore”) appeals from the jury verdict

finding her guilty of negligent homicide, criminal endangerment, and driving while her

privilege to do so was suspended; and the subsequent written judgment entered by the

Thirteenth Judicial District Court, Yellowstone County, on January 17, 2023. We affirm.

¶2 We restate the issues on appeal as follows:

Issue One: Whether the District Court erred when it denied Mullendore’s motion to dismiss the negligent homicide charge based on insufficient evidence.

Issue Two: Whether Mullendore’s counsel provided ineffective assistance of counsel.

Issue Three: Whether the District Court abused its discretion by allowing Officer Cook’s and Officer DeNio’s testimony.

Issue Four: Whether the District Court abused its discretion by denying Mullendore’s motion for a mistrial when Mullendore declined a curative instruction following Mullendore’s mother’s testimony that she had adopted A.R.

Issue Five: Whether the District Court erred by ordering Mullendore to pay Spencer, Sr. restitution for lost wages.

FACTUAL AND PROCEDURAL BACKGROUND

¶3 On November 23, 2019, Mullendore was driving an Acura with three children in the

car. Two of the children were Mullendore’s children: Spencer, aged 5, and A.R., aged 6.

Mullendore’s niece, T.K. aged 5, was also in the Acura. T.K. was placed in a booster seat

in the front passenger seat, and Spencer and A.R. were placed in the backseat with no car

seats.

¶4 On the same day, there was an accident between a different vehicle and a van on the

hill of 32nd Street South. Mullendore approached this accident site in the Acura. Shortly 2 thereafter, Joyce Duncan (“Duncan”) rearended the Acura in her Chevy Uplander. Duncan

was traveling approximately 31 miles per hour at the time of the crash. When Duncan

exited her vehicle, the Acura was gone.

¶5 Multiple witnesses testified at trial that the Acura took off down the hill at a high

rate of speed. One witness noted that the Acura “rev[ed] their engine really loud” and the

“tires screeched and took off down the hill.” He told law enforcement that the Acura

“accelerated really fast” and “straight pegged,” meaning “[t]he pedal is as far as it can go

down. As much gas as you can basically give a car.” The circumstances made this witness

think the driver of the Acura was running. Another witness testified that the Acura “got

pushed forward a little bit” but then “accelerated at a rapid pace.” He explained that the

Acura slowed after being rearended then accelerated as if two separate things happened.

He thought the driver was “speeding off, wanting to get out of there.” Another witness

believed Mullendore slammed on her brakes then slammed on the gas.

¶6 The Acura went off the road into a ditch and then came out of the ditch towards

oncoming traffic. A teenager was driving a Yukon up 32nd Street at this moment.

Mullendore swerved into the northbound lane. The Yukon driver turned the wheel slightly

to the right to protect another teenager in the passenger seat. Mullendore collided directly

with the Yukon.

¶7 As a result of the accident, Spencer was life flighted to Salt Lake City where he died

from fatal blunt-force injuries sustained during the crash. A.R. suffered various injuries,

3 including significant injury to her spinal cord leaving her permanently paralyzed below her

belly button.

¶8 The State charged Mullendore with vehicular homicide while under the influence

or in the alternative, negligent homicide; negligent vehicular assault or in the alternative,

criminal endangerment; various other counts of criminal endangerment; and driving while

her privilege to do so was suspended or revoked. The parties dispute whether Mullendore

was intoxicated at the time of the crash.

¶9 At the time of the crash, Mullendore’s license was suspended and she was not

permitted to have unsupervised contact with her children because of involvement with

Child Protective Services. Prior to trial, the District Court ordered that testimony on

Mullendore’s restricted parenting rights be limited.

¶10 Mullendore’s defense theory at trial was that the initial impact from being rearended

by Duncan in her Uplander was what caused the Acura to accelerate and collide with the

Yukon. The State’s theory was that Mullendore intentionally fled the scene after being

rearended because she was in custody of the children when she was not permitted to be.

Mullendore specifically contends that the State did not meet its burden in proving

Mullendore was the cause-in-fact of Spencer’s death.

¶11 Officer Cook, the primary crash investigator, testified on behalf of the State. He

opined on the speed and trajectory of the Acura. Officer DeNio, another member of the

crash investigation team, also testified on behalf of the State. She offered additional

4 testimony on the trajectory of the Acura. Mullendore challenges various parts of their

testimony on appeal.

¶12 At the close of a six-day jury trial, the jury found Mullendore guilty of negligent

homicide, criminal endangerment, and driving while her privilege to do so was suspended.

Mullendore raises various issues, each of which are discussed below.

¶13 Additional facts are provided herein where necessary.

STANDARD OF REVIEW ¶14 We review de novo a district court’s denial of a defendant’s motion to dismiss for

insufficient evidence. State v. Bowen, 2015 MT 246, ¶ 21, 380 Mont. 433, 356 P.3d 449.

“We review de novo whether sufficient evidence supports a conviction.” State v.

Christensen, 2020 MT 237, ¶ 11, 401 Mont. 247, 472 P.3d 622. When considering a

challenge based on the sufficiency of the evidence, we determine “whether, after reviewing

the evidence in the light most favorable to the prosecution, any rational trier of fact could

have found the essential elements of the crime beyond a reasonable doubt.” Christensen,

¶ 11.

¶15 “Only record-based ineffective assistance of counsel claims are considered on direct

appeal.” State v. Howard, 2011 MT 246, ¶ 18, 362 Mont. 196, 265 P.3d 606. Ineffective

assistance of counsel claims are mixed questions of law and fact, which we review de novo.

State v. Santoro, 2019 MT 192, ¶ 11, 397 Mont. 19, 446 P.3d 1141.

¶16 This Court reviews a district court’s determination regarding the qualification and

competency of expert witnesses for abuse of discretion. State v. Harris, 2008 MT 213, ¶ 6,

344 Mont. 208, 186 P.3d 1263.

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