Breaking his public silence for the first time since George Floyd's killing, ex-Minneapolis police officer Tou Thao testified Tuesday that he was focused on crowd control and believed his three colleagues were looking after Floyd during the arrest.

Under questioning from his attorney Robert Paule, Thao testified that he didn't realize Floyd was in medical distress until Minneapolis firefighters arrived on the scene after an ambulance had already taken Floyd away.

"Was it at that point that something sunk in?" Paule asked.

"Yes," Thao said, adding that until then he "had no idea" something serious had happened to Floyd.

Floyd died on May 25, 2020, after former Minneapolis officer Derek Chauvin knelt on his neck for more than nine minutes while colleagues J. Alexander Kueng and Thomas Lane helped pin Floyd stomach-down in the street. Floyd's hands were handcuffed behind his back.

Thao kept a crowd of increasingly angry bystanders at bay as they yelled at the officers to relent and to check Floyd's pulse once he grew unresponsive. He characterized his job as "full-time crowd control."

Thao, 36, was on the stand much of the day and came off as calm and mostly direct in response. He made a joke about his toddler that caused the judge to chuckle. Under cross-examination, he was not angry or defensive although he was occasionally evasive.

He testified that he expected his three colleagues to address any medical needs that arose during the arrest because he had positioned himself in the street as a "human traffic cone" to alert drivers to the officers' presence in the roadway and was preoccupied with keeping agitated bystanders from getting too close.

Paule ended his 2-hour, 45-minute questioning of Thao with a pointed question. "At any point did you touch Mr. Floyd?" he asked.

"I did not," Thao said.

In her cross-examination, Assistant U.S. Attorney LeeAnn Bell got Thao to admit that Floyd appeared unconscious at the scene, that officers have a duty to intervene when colleagues break the law and that delaying CPR for even a minute could greatly diminish a person's chances of survival.

She and the defense attorneys, especially Paule, sparred over how much video she could play when she wanted to show that Thao was standing near Chauvin with a clear view of his knee on Floyd's neck for the first six minutes.

She asked Thao what he observed the officers doing in the third minute of the restraint.

He responding, "Restraining."

She asked, "How?"

He said, "Same thing."

She said, "Same position?"

He said, "Generally, yes."

She posted still images of the scene showing Thao near Chauvin and looking down. "If you're looking down, you knew what was going on and you knew that Floyd had stopped resisting," she said.

Thao responded, "It's a possibility."

Several police body camera and bystander cellphone videos showed that none of the officers performed CPR on Floyd before paramedics arrived. Lane boarded an ambulance with Floyd and began chest compressions at a paramedic's direction.

"You know from your training that it's critical to begin CPR before the paramedics get there, right?" Bell asked.

"If it's safe to do it," Thao said.

Thao, Kueng and Lane are being tried jointly in federal court. They are accused of violating Floyd's constitutional right to be free from unreasonable seizure by failing to provide medical aid. Thao and Kueng also are charged with failing to intervene on Floyd's behalf to stop Chauvin.

Thao was the second witness called as his defense began. Kueng and Lane have said they will testify as well.

Thao began his testimony by recounting a troubled childhood with an abusive father that inspired him to pursue police work. He also talked about his time at the Minneapolis police academy where recruits were routinely allowed to use their knees to pin subjects stomach-down in training scenarios.

Thao told jurors that he decided to become a police officer after flunking out of community college in his first semester and a stint working at Cub Foods. He choked up as he recounted how he first encountered Minneapolis police when he was 7 or 8 and his father beat him and his younger brother with an extension cord to break up a fight.

When their mother intervened, Thao said, their father beat her, then retrieved a gun and threatened to kill them. The family fled to an aunt's house where they called 911.

Bell objected a few times to Thao's testimony, but was overruled by U.S. District Judge Paul Magnuson, who said Thao could testify about his background.

Born in St. Paul, Thao spent much of his childhood in north Minneapolis before his family moved to Fridley when he was 10. He said they were so poor they ate one meal a day and had two meals a day if school was in session. He is married and has two daughters, ages 5 and 2, and a 1-month-old son.

Paule showed jurors several photos from Thao's academy training that showed multiple recruits using their knees on different parts of subjects' backs to pin them stomach-down on the ground while handcuffing them. A photo from a 2009 training showed Thao with another recruit positioned over an actor prone with their hands behind their back. Thao explained that he and his classmate used their knees to restrain the actor.

"Just to be clear, is this something that was typically taught at the academy when you were there?" Paule asked.

"Yes," Thao said.

On May 25, Thao testified that dispatch had called off him and Chauvin, saying the Floyd arrest scene was OK. But they went anyway to help. "From my experience Cup Foods is hostile to police," Thao said. "It's a well-known Bloods gang hangout."

Although he pulled a hobble device out of a bag in the squad vehicle, Thao testified that officers decided against using it because it would have complicated matters for the ambulance crew on its way to the scene if Floyd had been "tied up like a Christmas present," he said.

He said that based on his experience working security at a local hospital he believed Floyd was on drugs and in a state of "excited delirium."

Paule asked Thao why he didn't participate in the restraint or medical evaluation of Floyd.

"Because at that point I have a different role," he said, adding that he was doing "crowd control."

Jurors convicted Chauvin last April in state court of murdering Floyd. Chauvin later pleaded guilty in federal court to violating Floyd's civil rights.