ST. LOUIS – The trial of a man accused of killing St. Louis Police Officer Tamarris Bohannon four years ago is underway.

Thomas Kinworthy’s defense admits he pulled the trigger, killing Bohannon, but argues a mental illness prevented him from knowing what he was doing. The 47-year-old shot and injured Bohannon’s partner as well.

Kinworthy’s defense says he should not be found guilty of first-degree murder or for wounding another officer in August 2020.

“Tommy suffers from a serious mental illness…called schizoaffective disorder. He had come to St. Louis from out of town…and was starting to have paranoid delusions,” Public Defender Annie Legomsky said. “In the hours leading up to this incident, Tommy was again experiencing these paranoid delusions that he thought people were coming to get him.”

During trial Monday, Kinworthy could be seen rocking back and forth in his seat. Prosecutors argued that he had broken into another home, shooting a homeless person before shooting at the police.

“We’ll ask you to find him guilty at the end of this case,” Prosecutor Tanja Engelhardt said. “For murder in the first degree, for killing a husband, a father, a son, and an excellent police officer.”

Alexis Bohannon was the first person to take the stand with tears as she described her late husband.

“I made the decision to take him off life support because he was starting to seize,” she said.

Officer Bohannon was 29 years old when he was killed, having served with the department for three and a half years. He left behind his wife and three children.

Prosecutors said Bohannon and his partner were ambushed after arriving at a home near Tower Grove Park in south St. Louis. Bohannon was shot in the head from a second-story window, and his partner was shot in the leg.

Kinworthy was arrested after a standoff that lasted nearly 12 hours.

The trial is expected to take two weeks.