The graphic video showed two Los Angeles police officers handcuffing an unarmed man who had just been shot and whose head was covered in blood.
The video, which was circulated on social media on Saturday, prompted questions as to why police would handcuff a man who was seriously injured. The unidentified man remains in critical condition.
Cmdr. Andrew Smith, a spokesman for the Los Angeles Police Department, said the officers followed standard procedure in handcuffing the man when they did. At that point, Smith said, the man had not been searched and was considered a suspect.
"We always do that," Smith said. "That's the policy ... to handcuff someone in a situation like that."
Police shot the man after he approached officers and raised his arm, wrapped in a towel. They thought he had a gun, but he turned out to be unarmed.
The incident began when the man flagged down officers about 6:35 p.m. Friday at Los Feliz Boulevard and Tica Drive south of Griffith Park, according to a police account.
"This person extended an arm wrapped in a towel. The officer exited the vehicle and said, 'Drop the gun! Drop the gun!'" LAPD Lt. John Jenal said.
Then at least one officer shot the man, officials said. The man then collapsed on the ground.
A motorist shot video of the officers rolling over the wounded man and handcuffing him, even though he did not appear to be resisting and the back of his head was covered in blood.
Cmdr. Smith cautioned that the investigation into the shooting was still in its early stages. One of the key questions, he said, was why the man flagged down the two uniformed officers.
The man was standing on the side of the road, Smith said, when he called out to the officers: "Police, police."
Smith said investigators would explore all possibilities, including whether the man needed some type of help from police. He said investigators would also look into the man's background to see if there were any indications the shooting was an attempted "suicide by cop."
The man's name has not been released.
"We cover everything. Our investigators leave no stone unturned," Smith said. "We don't have any idea about this guy's background. We just don't know yet."