WASHINGTON — A black motorcyclist posed no threat to the life of the District of Columbia police officer who shot and killed him, an attorney for the man’s relatives said Thursday as he called for city officials to release more information about the circumstances of the shooting.

Attorney Jason Downs said many unanswered questions remain about the death of Terrence Sterling, 31, of Fort Washington, Maryland, but he said Sterling, who was unarmed, did not collide with a police car with any great force. Police have said Sterling was shot after he intentionally rammed the passenger-side door of a police car while trying to flee a traffic stop.

The officer who shot Sterling, 27-year-old Brian Trainer, a four-year veteran of the department, was wearing a body camera, but he did not turn it on until after the shooting, police said. Police have not disclosed the officer’s race. Downs said his understanding is that the officer is white.

“From witness accounts, Mr. Sterling wasn’t doing anything to present a threat to this particular officer and in fact, this officer is violating a general order by trying to block Mr. Sterling in,” Downs said Thursday. “It appears that Officer Trainer fired his weapon from the safety of his police vehicle when Mr. Sterling did not pose any threat to him whatsoever.”

Trainer has been placed on administrative leave, as is routine in cases when officers fire their weapons.

Downs spoke to reporters alongside Sterling’s parents, sister and aunt, all of whom declined to comment. Downs said they were still grieving and stunned by the body-camera footage they viewed Wednesday of Sterling bleeding on the sidewalk from a gunshot wound to the neck as an officer performed CPR. Sterling died of wounds to the neck and back, according to the city’s chief medical examiner, who did not detail how many times Sterling was shot.

The family was allowed to see an additional 60 to 90 seconds of body-camera footage that was not made available to the public, Downs said. That footage shows a police union representative arriving to assist the officer who shot Sterling and advising him to turn his camera off, Downs said.

The hasty arrival of the union representative raises questions about whether police officers called the union before calling an ambulance for Sterling, he said.

According to a timeline released by city officials, gunshots were heard just before 4:30 a.m. and two ambulances were dispatched at 4:30 a.m., arriving within minutes.

Downs also said it’s likely that additional video exists of the shooting, either from surveillance cameras in the area or from high-resolution satellite cameras that monitor the nation’s capital, and he called on city officials to release any such footage as soon as possible.

A spokeswoman for Mayor Muriel Bowser, Nicole Chapple, said she is not aware of any additional video and that if it exists, it would remain in the possession of investigators from the U.S. Attorney’s office.

Sterling had worked as a heating and air conditioning technician for 12 years, Downs said. He refused to release additional details about Sterling’s personal life.

It’s not clear what Sterling was doing in Washington in the early-morning hours of Sept. 11 when he was shot. Police said officers stopped Sterling after getting a report of a motorcyclist driving erratically, but Downs said he’s not certain that Sterling was the same motorcyclist who prompted the initial report.

His death has led to protests from activists affiliated with the Black Lives Matter movement.

“The family is hopeful that any protests moving forward remain peaceful,” Downs said, “but peace is only possible if this investigation is completely transparent.”

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