Minutes later more officers arrived and the team handcuffed Mr. Clark, who lay mortally wounded.

As other officers arrived, the two involved in the shooting muted the audio feeds to their body cameras. One of the officers was black and the other was white. They are both on paid leave, Mr. Hahn said.

Timothy Davis, president of the Sacramento Police Officers Association, called the event a tragedy and voiced his support for the officers involved. “No police officer ever wants to have to take a life,” Mr. Davis said. “Our officers are out there serving this community, leaving their family behind to serve this community.”

It remains unclear if the decision to mute the cameras went against official protocol, but the act alone has prompted intense suspicion. The Clark family’s lawyer, Benjamin Crump, said that the move “reeks of impropriety” and that the Police Department was trying to cover something up. Mr. Crump represented the families of Trayvon Martin, who was shot by a neighborhood watch volunteer in 2012, and Michael Brown, killed by the police in Ferguson two years later.

Mr. Hahn said that the department could not explain why the officers muted their cameras, but that the officers’s actions were under investigation. The department had been considering banning muting cameras outright before Mr. Clark was shot, he said.