CHICAGO — A veteran Chicago Police sergeant tearfully testified Wednesday that, after a controversial 2017 police shooting, he was removed from the CPD’s Detective Division “for not going along with a BS shooting.”

“I didn’t do what they wanted me to do,” CPD Sgt. Isaac Lambert said. “I did what was right and I got screwed.”

Lambert filed a whistleblower lawsuit against the city in 2019 that alleges he was removed from the CPD’s Detective Division — “dumped” in police parlance — after he expressed concerns about the legality of the 2017 shooting of an unarmed teen with autism by an off-duty CPD officer on the Far South Side.

“Just didn’t think it would happen to me for just doing my job, standing up for a kid who couldn’t stand up for himself,” Lambert said.

He also testified that the department’s initial investigative response to the shooting gave him more cause for concern.

Lambert told jurors that, in the hours after the shooting, he was part of a large meeting with several of his superiors at the offices of Area South Detectives. During that meeting, Lambert said, he was concerned by the apparent willingness of CPD higher-ups to classify CPD Sgt. Khalil Muhammad as the victim in the incident and bring aggravated assault charges against Ricardo Hayes — an unarmed 18-year-old with autism who was recently reported missing.

“The silence from the bosses was somewhat deafening,” Lambert said, “Almost like they condone it or they’re willing to make the situation right for the copper.”

Lambert, who joined the CPD in 1994, further testified that he thought Muhammad was not only unjustified in the shooting, but that the sergeant could potentially face criminal charges for his actions.

Lambert, who was on the witness stand for more than four hours Wednesday, told jurors that Muhammad could not give a good reason for why he shot Hayes in the 10900 block of South Hermosa in the early hours of Aug. 13, 2017.

“He could not articulate any crime committed by Hayes,” Lambert said of Muhammad. “Not one time did he give us anything that stated this kid committed a crime against a person, something violent in nature, that would require him to use deadly force.”

After the shooting, Hayes’ family filed a lawsuit against the city that was later settled for more than $2 million. The Chicago Police Board later ordered Muhammad suspended for six months for shooting Hayes.

J.T. Wilson III, an attorney representing the city, began cross-examining Lambert in the afternoon. Wilson repeatedly pressed Lambert on why, if he believed a cover-up of the shooting was ongoing, he did not contact any other outside law enforcement agencies.

Earlier Wednesday, Lambert said he first learned of home surveillance video that captured the shooting in October 2018 when he saw the footage broadcast on the local news.

“You did not, after you saw that video, you didn’t contact the Cook County State’s Attorney’s Office to say, ‘Hey, there’s a cover up here,’ did you?” Wilson asked.

“No, sir,” Lambert replied.

In her opening statement Tuesday, city attorney Michelle Rakestraw told the jurors that the evidence in the trial would show Lambert was an inattentive and ineffectual supervisor of other detectives, and that his reassignment to the Patrol Division was for good cause.

After he was reassigned to the Patrol Division in February 2019, Lambert said he contacted the CPD’s Employee Assistance Program, the department office responsible for aiding officers in need of mental health aid. Lambert eventually opted to go on medical leave to address the stress brought on by his reassignment as he was — and still is — “just having a difficult time coping with what happened.”

Though he was still paid his base salary of about $108,000, Lambert was unable to qualify for overtime assignments. In the years before his reassignment, Lambert said, he routinely collected more than $40,000 in overtime pay annually.

Lambert’s testimony is expected to continue Thursday, and the trial is scheduled to last through mid-December. His lawsuit seeks his return to the Detective Division and for wages lost.