A Collin County jury Thursday imposed five life sentences on a man who had pleaded guilty to shooting a state trooper and launching a 15-hour standoff at a Frisco apartment complex in 2019.

Bryan Cahill, 44, pleaded guilty Monday to seven charges of evading arrest, aggravated assault with a deadly weapon and aggravated assault with a deadly weapon against a public servant. He elected to have a jury decide his sentence after hearing testimony this week.

After several hours of deliberation, the jury returned life sentences for the five charges of aggravated assault against a public servant, 20 years for the charge of aggravated assault and 10 years for the evading arrest charge.

His mother, Christine Cahill, testified that her son had shown signs of mental impairment and violent tendencies from an early age. She had called police shortly before the Frisco shooting, saying he’d threatened neighbors and others.

In an opening statement, prosecutor Dewey Mitchell said that although there were “decades of people trying to get [him] right,” he deserved to be locked up for life.

“Bryan Matthew Cahill is a threat wherever he is,” Mitchell said.

Texas Department of Public Safety Trooper Travares Webb testified Monday that he had pulled Cahill over for driving 125 mph on the Dallas North Tollway on March 29, 2019. Webb asked Cahill to step out of the vehicle and said he’d take him to jail for reckless driving.

Dash-cam video from Webb’s vehicle shows Cahill looking from side to side before starting to move back toward the driver’s door.

“Stand right there,” Webb shouted. “Do not go back to your car, do you understand that?”

“I can’t do this,” Cahill said.

“Do you understand what I’m telling you to do?” Webb said. “Do not go back to your car.”

“Yes, sir,” Cahill said.

Webb turned away, and Cahill ran back to the vehicle and sped off.

He drove to the La Valencia at Starwood apartments in the 6800 block of Lebanon Road, where he opened fire on Webb with a .40-caliber Glock and a shotgun loaded with slugs. Video obtained by The Dallas Morning News showed the trooper was wounded in the leg before backup arrived.

Another apartment resident testified Tuesday that he heard gunfire and opened his window to intervene. Zachary Pence, a former Army soldier who had been trained in urban combat to serve in Afghanistan, testified Tuesday that he fired at Cahill with a handgun when he saw Webb was injured.

“I knew backup was on its way,” Pence testified. “My goal was to distract him long enough so backup could get here and Trooper Webb could stay safe.”

Cahill then fled to his own apartment, and Webb shot him in the hip.

Webb was taken to the hospital and underwent surgery that night, as SWAT officers surrounded Cahill’s apartment, where he had barricaded himself.

Cahill was taken into custody about 5 the next morning, after firing on officers during negotiations, police said.

Mental health questioned

In jail, Cahill received regular mental health treatment and psychological evaluations. A forensic psychologist who testified for the defense, Antoinette McGarrahan, said Cahill had “significant impairment” in cognitive ability, including in decision-making and memory.

She said he had brain damage and that there were a number of potential causes or diagnoses for his mental illness, which could cause lifelong problems.

“They are significantly impairing his ability to function independently,” McGarrahan said. “It’s going to affect him quite substantially.”

Another psychologist, Matthew Clem, testified that he had diagnosed an unspecified personality disorder in Cahill.

He said that Cahill was difficult to talk to in clinical interviews and that he didn’t want to discuss the incident in March 2019.

While Clem was testifying, Cahill cursed loudly in the courtroom.

“Mr. Cahill, don’t make me warn you again,” Judge Benjamin Smith said sternly. “I don’t want to hear any comments on the questions or the answers, and certainly no profanities. Do you understand me?”

“I’m not sure,” Cahill said, raising his eyebrows.

“You’re not sure?” the judge said. “I don’t want to hear your voice in this courtroom unless you are testifying. Do you understand?”

‘I’m not going to stop’

According to multiple jail calls played at the trial, he also regularly spoke to his mother after his arrest.

She cautioned him to not speak about the case because the calls were being recorded, but he angrily berated her and used slurs against the trooper he had shot, Mitchell and even his own attorneys.

“I’m not going to stop, I’m never going to stop, they’re not going to stop me,” Cahill told his mother on a jail call.

Catherine Cahill said that because her son struggled with mental illness, she wanted the jury to allow him to seek treatment out of the custody of the state.

“I’d like for them to see the other side of Bryan, which is very kind and generous and caring,” Catherine Cahill said. “I just would hate to come to this point and not offer him that opportunity for some treatment.”