An investigation into the shooting of an unarmed black man as he lay on the ground with his hands in the air is being undertaken by the Florida Department of Law Enforcement, North Miami's police chief says.
A mobile phone video showed behavioural therapist Charles Kinsey with his hands extended above his chest moments before a bullet struck his leg.
The shooting occurred in North Miami while Kinsey was trying to get an autistic man back to a nearby group home from which he had wandered.
Kinsey works at the home, which is operated by the Miami Achievement Center for the Developmentally Disabled.
US Attorney General Loretta Lynch said the Justice Department was gathering information about the incident, the latest in a series of controversial shootings of black men by police in the United States.
Kinsey told Miami's WSVN-TV that he was trying to calm the autistic patient when police showed up on Monday evening. Media reports have said Kinsey is 47 years old.
Kinsey said he dropped to the ground and lay on his back with his hands up and open to comply with commands from the police officers.
"As long as I've got my hands up, they're not going to shoot me. This is what I'm thinking," Kinsey said in an interview with WSVN-TV from his hospital bed on Wednesday. "Wow, was I wrong."
Kinsey said he kept his hands up throughout the incident and that he asked the officer, "Sir, why did you shoot me?"
"He said, 'I don't know.'"
Mr Kinsey's attorney, Hilton Napoleon, said there was no way police could validate the decision to shoot his client.
"There is no justification for shooting a man who's laying on his back and telling you that he's unarmed, that he's a mental health professional and that he's attempting to assist someone who clearly has behavioural issues because he's autistic," he said.
"He also explains to police … that the instrument in the autistic guy's hand is a toy truck - and when you look at the video, there is no argument that can be made that that [looks like] a gun."
Police said in a statement that the officers were responding to a 911 call about an armed man threatening suicide. They said the officer, who has not been identified, is on administrative leave according to standard procedures.
The shooting itself was not recorded, but in the video, which has been widely circulated on social media, Kinsey can be heard talking to his patient and police while lying flat in the street.
"All he has is a toy trunk in his hands ... I am a behaviour therapist at a group home," Kinsey yelled in the video. He also urged his patient, who was sitting nearby, to lie down and be still.
The autistic man told him to "shut up" and did not comply.
The United States has seen demonstrations from coast to coast over the use of excessive force by police, especially toward black men.
Reuters / Newshub.