The Nebraska Supreme Court has left standing Dr. Mark Carlson’s manslaughter conviction and prison sentence in the 2023 Dodge Street crash that killed 22-year-old Anna Bosma. Carlson was convicted by a jury in February 2025 and sentenced the following month to 10 to 14 years in prison.
Prosecutors said Carlson was racing another driver in his Mercedes during Labor Day weekend 2023 when he lost control on Dodge Street in front of the University of Nebraska Omaha and slammed into oncoming traffic, according to 1011now.com. Bosma, who had just graduated from college, was killed in the crash, as reported by WOWT.
Appeal Centered on a Possible Medical Episode
Carlson argued that jurors should have been instructed to consider whether an unexpected, unavoidable medical event—such as fainting—caused him to lose control. Instead, they were instructed that manslaughter required finding that he acted without malice and unintentionally while committing an unlawful act. In this case, the unlawful act was reckless driving, defined for jurors as disregard for or indifference to another person’s safety or the consequences of one’s actions, according to the 1011now.com report linked above.
Carlson also challenged a prosecutor’s closing argument that being unconscious does not automatically mean a defendant is not guilty. The state argued that the instructions were adequate and that the evidence did not support adding language about fainting, the report said.
Justices Reject Every Argument
The justices rejected Carlson’s arguments, finding that the prosecutor had not misstated the law or sought a conviction without consideration of Carlson’s mental state. They also concluded that the instructions would not have allowed a conviction if jurors believed an unexpected, unavoidable medical event caused the crash while Carlson was otherwise driving lawfully, according to the report.
State law distinguishes manslaughter involving a motor vehicle from the separate motor-vehicle homicide statute, and provides that a person convicted under the manslaughter provision is sentenced under that law, according to the Nebraska Legislature. The law also distinguishes reckless driving from willful reckless driving based on intent; a person cannot commit the willful version without also committing ordinary reckless driving, according to the Nebraska Legislature.
Sentence Stands, Family Calls It Justice
News reports have differed on the sentence’s length: 1011now.com reported Carlson received 10 to 14 years in March 2025, while an earlier WOWT report described a sentence of up to 10 years. 1011now.com reported that, under Nebraska law, Carlson would likely be released after five years.
Omaha’s broader traffic-safety efforts
The City of Omaha says its citywide Vision Zero strategy aims to eliminate all traffic fatalities and severe injuries on its transportation system by 2045. That goal does not speak to the specific circumstances of Carlson’s crash.
Separately, 3 News Now reported that during the first year an Omaha street-racing ordinance was in place, police cited or arrested 42 people directly involved in street racing and impounded 12 vehicles. Those figures do not establish a trend in crash frequency or a connection to Carlson’s case, according to 3 News Now.
Bosma’s family said the verdict and sentence represented justice served. The Supreme Court’s ruling leaves Carlson’s conviction and prison term in place.
