ST. PAUL, Minn. (AP) — Two former Minneapolis police officers charged in George Floyd’s killing took the witness stand Wednesday at their federal trial to challenge prosecutors’ contention that they violated their training and should have intervened to stop Officer Derek Chauvin from kneeling on the Black man’s neck.

J. Alexander Kueng and Tou Thao are charged, along with Thomas Lane, with violating Floyd’s constitutional rights. Kueng knelt on Floyd’s back, Lane held his legs and Thao kept bystanders back while Floyd, 46, was handcuffed, facedown on the street.

Thao took the stand for a second day, testifying that he knew Floyd’s pleas that he couldn’t breathe were becoming weaker, but still did not realize Floyd was in danger even as bystanders became increasingly vocal.

Under cross-examination by prosecutor LeeAnn Bell, Thao said he did not relay any of the onlookers’ concerns about Floyd’s well-being to the other officers, and did not check Floyd’s pulse after bystanders asked him to. He said he was relying on the other three officers at the scene to care for Floyd’s medical needs while he controlled the crowd and traffic, and that he didn’t think Chauvin’s knee was on Floyd’s trachea.

Kueng began his testimony by describing his training, including how to secure a scene and the need to check someone’s neck pulse if they’re in distress.

Lane is also expected to testify.

Thao, Kueng and Lane are accused of depriving Floyd of medical care. Kueng and Thao are also accused of failing to intervene to stop the May 2020 killing, which triggered protests worldwide and a reexamination of racism and policing. The charges allege that the officers’ actions resulted in Floyd’s death.

Prosecutors argue that the officers should have intervened to stop Chauvin and that they violated their training by not rolling Floyd onto his side so he could breathe, or giving him CPR as soon as he stopped breathing and they could not find a pulse.

Defense attorneys contend the Minneapolis Police Department provided inadequate training and taught cadets to obey superiors. Chauvin, who was convicted of state murder and manslaughter charges last year, was the most senior officer at the scene.

On Wednesday, Bell asked Thao what steps officers took to help Floyd. He replied that they were waiting for paramedics. She also asked if he ever told Chauvin to get off Floyd.

“I did not,” Thao replied, adding later that, “I think I would trust a 19-year veteran to figure it out.”

When Bell asked Thao if he communicated any bystander concerns to his partners, he replied, “Nope.”

Thao’s attorney, Robert Paule, asked why officers thought it important to keep Floyd restrained and Thao said they believed Floyd was in a state of “excited delirium” — a disputed condition in which someone is said to have extraordinary strength — and needed medical care from paramedics “that we were not capable of doing.”

Paule asked if they intended to cause Floyd harm.

“Oh no,” Thao replied.

Thao told his attorney that he understood Floyd’s condition was critical when the fire department was asked to assist paramedics who had taken him to another location.

He also agreed with the prosecutor that when he called for a more urgent paramedic response, he knew it was “life or death.” She asked if he radioed back to tell them he suspected excited delirium or that Floyd was not talking or unconscious, and Thao said no.

Lane, who is white; Kueng, who is Black; and Thao, who is Hmong American, also face a separate state trial in June on charges alleging that they aided and abetted murder and manslaughter.

Chauvin, who is white, pleaded guilty in December to a federal civil rights charge.