A driver’s description of an assault and vehicle helped officers find Dhoua Lao before the case became a murder prosecution.
ROSEVILLE, Mich. — The murder case against Martin Yost began not in a courtroom but with another driver reporting an assault inside a moving or occupied vehicle and giving police enough information to begin searching for the car.
Roughly 30 minutes after that report on Nov. 13, 2023, officers in Roseville located a vehicle matching the description on Gratiot Avenue near Interstate 94. Yost was unconscious or incapacitated in the driver’s seat, authorities said. His girlfriend, Dhoua Lao, was in the passenger seat and had died. The discovery launched an investigation that continued for more than two years and ended June 12, when a Macomb County jury convicted Yost of first-degree premeditated murder after a two-week trial.
The initial witness played a limited but critical public role in the case. Macomb County Prosecutor Peter Lucido said the driver saw a man assaulting a woman inside a car in Detroit and called 911. The witness supplied a description of the vehicle, allowing police in a neighboring community to identify it later. Public reports have not named the witness or disclosed a complete transcript of the emergency call. Still, the timing described by authorities established an early link between the reported assault and the car in which officers found Yost and Lao.
The location where officers discovered them was several miles from where investigators believed the fatal assault occurred. WDIV reported that police believed Lao had been attacked in Detroit, placed in the vehicle and driven to Roseville. That sequence gave investigators more than one possible scene to examine: the location of the assault, the vehicle itself and the roadside area where the car stopped. Public accounts have not provided a complete route, an exact Detroit address or an explanation of why the vehicle came to rest near Gratiot Avenue and I-94.
Inside the car, officers encountered circumstances that quickly turned the response into a homicide investigation. Authorities said Yost was covered in blood. Lao had suffered major injuries to her head, face and hands, and officers determined she was dead. Lucido later said the injuries to her hands appeared consistent with defensive wounds. Reports from the trial described her condition in unusually severe terms. Those descriptions have been limited here because the essential fact is that medical and physical evidence showed a prolonged and fatal assault, not the graphic appearance of its aftermath.
Investigators then had to connect the witness account, the vehicle and the physical evidence to a legally provable sequence. Finding Yost beside Lao’s body was highly significant, but a murder conviction required prosecutors to establish more than presence. They needed to prove that Yost caused her death and, for first-degree premeditated murder, that the killing was willful, deliberate and premeditated. The prosecution therefore developed evidence about what happened before the car was found, what the couple had communicated and what the injuries showed about the nature of the attack.
Text messages presented during the trial gave jurors a view of Lao’s fear before her death. According to a courtroom report cited by Law&Crime, she had pleaded with Yost not to kill her and offered him money not to hurt her. Prosecutors used those communications to describe a disturbing relationship marked by threats and violence. The messages supplied context that the roadside discovery could not provide on its own. They also allowed jurors to consider whether the killing followed earlier statements or conduct relevant to the prosecution’s claim of premeditation.
Authorities arrested Yost and initially charged him with second-degree murder. He was arraigned Nov. 16, 2023, in Roseville District Court and ordered held in the Macomb County Jail. At that point, the prosecutor’s office carefully described the killing as an allegation, as required before trial. Yost remained in custody without bond as the case moved through preliminary proceedings and into Macomb County Circuit Court. The record available through public reports does not explain when prosecutors pursued first-degree murder or provide the full language of any amended charging document.
By the time the case reached trial before Circuit Court Judge Rachel Rancilio, prosecutors were asking jurors to find the killing premeditated. Over two weeks, the jury heard evidence about the emergency report, the police discovery, Lao’s injuries, communications between the couple and other circumstances surrounding her death. Reports did not provide a full daily transcript or a complete summary of the defense case. That limits any independent assessment of individual arguments, but the final verdict shows jurors accepted the prosecution’s proof on every element of first-degree murder.
Yost, now 45, was convicted June 12. Lao was also 45 when she died and was the mother of two, according to WDIV. The verdict transformed the roadside investigation into a completed trial judgment and exposed Yost to the most severe punishment available under Michigan’s murder law. For an adult convicted of first-degree premeditated murder, the statute requires life imprisonment without eligibility for parole. Sentencing is set for July 28 in Macomb County Circuit Court.
The case also drew attention because Yost had recently completed parole before Lao’s killing. News reports said he had prior convictions that included domestic violence, carrying a concealed weapon and fleeing police. His most recent domestic violence conviction was in 2020, and he had been off parole for about three weeks when officers found him with Lao. Lucido said investigators did not know whether Lao was aware of that record. The prosecution did not need to prove what Lao knew to establish the murder charge, but the history added context to official statements describing the killing as domestic-violence related.
After the verdict, Lucido said the conviction reflected the work of prosecutors, investigators and Lao’s family. He described the death as an example of the worst outcome of domestic violence and acknowledged that a verdict could not restore what the family lost. Chief Assistant Prosecutor Sian Hengeveld and Assistant Prosecutor Erica Clute-Cubbin handled the case for the prosecution, according to the county. Public reports reviewed for this article did not include a statement from Yost or his attorneys after the jury’s decision.
The emergency caller’s observation did not by itself decide the case, but it shaped everything that followed. It gave officers a vehicle to find, established a timeline close to the assault and placed outside attention on conduct that might otherwise have remained hidden inside the car. Police then preserved the scene and gathered evidence that prosecutors later placed before the jury. More than two years afterward, the witness report remained the first publicly identified step in the chain that led to Yost’s conviction.
At sentencing, the court is expected to formally impose the punishment required by Michigan law and may hear statements concerning Lao and the effects of her death. Yost remains in the Macomb County Jail without bond. No appeal had been announced in the sources reviewed as of July 15, and any future challenge to the conviction would proceed separately from the scheduled sentencing.
Author note: Last updated July 15, 2026.