(CNN) The police shooting of an African-American caregiver, who was lying in the street trying to help an autism patient, was accidental, according to the local police union representing the North Miami officer.

The officer had intended to shoot the patient, whom he thought posed a danger, but accidentally shot the caregiver instead, said John Rivera, the President of the Dade County Police Benevolent Association.

Charles Kinsey, a behavior therapist, was shot Monday by police -- an incident which has sparked outrage. Footage released by Kinsey's attorney showed his client lying on the ground holding both hands in the air, next to a 23-year-old man with autism.

Rivera offered an explanation Thursday, saying that the police officer opened fire because he thought the white individual, whom they later learned is a man with autism, was going to harm Kinsey.

"This wasn't a mistake in the sense that the officer shot the wrong guy or he thought that Kinsey was the bad guy," he said in a press conference Thursday.

"The movement of the white individual made it look like he was going to discharge a fire arm into Mr. Kinsey and the officer discharged trying to strike and stop the white man and unfortunately, he missed the white male and shot Mr. Kinsey by accident."

Rivera said that the video footage of the incident was "being portrayed poorly."

Kinsey is hospitalized with a gunshot wound to his right leg after two or three shots were fired, according to his attorney.

"Mr. Kinsey did everything right, let's be real clear about that," Rivera said. He said that the police officer involved in the shooting "wishes nothing but the best for Mr. Kinsey and the officer is praying for his speedy recovery as are we."

Kinsey told CNN affiliate WSVN that after the shooting, he was flipped over and handcuffed. A video released by the attorney showed Kinsey lying in the road, on his stomach and handcuffed. Both men were seen flat on the ground with two officers standing near them. According to his attorney Hilton Napoleon II, Kinsey was on the ground for 20 minutes before an ambulance arrived.

North Miami police said the officer opened fire after attempting to negotiate. Kinsey and his attorney said that the police explanation doesn't add up. State authorities said they're investigating the incident.

The unidentified officer has been placed on administrative leave and he issued a statement in form of a text message, which was read aloud to the media by Rivera.

"I took this job to save lives and help people," according to the officer's text statement. "I did what I had to do in a split-second to accomplish that, and hate to hear others paint me as something I'm not."

Police: Caller reported armed man

A 911 call about an armed man threatening suicide drew officers to the scene just after 5 p.m. Monday, North Miami police Chief Gary Eugene told reporters.

"Our officers responded to the scene with that threat in mind. We had witness statements that there was a gun. We had a 911 call with that same information," Eugene said Thursday. "However, I want to make it clear, there was no gun recovered."

Kinsey told WSVN that his patient was holding a toy truck, not a firearm. He said he tried to explain the situation to officers.

Cell phone footage showed Kinsey lying in the street with his hands in the air.

"All he has is a toy truck," he shouted. "I am a behavior therapist at a group home."

Rivera, the president of the local police union, said that the officers had not heard what Kinsey was yelling.

Kinsey said the footage, released by his attorney, showed the moment Monday when he tried to persuade North Miami police not to harm his patient. He asked his patient to be still and lie down.

"Please be still ... get down ... lay on your stomach," Kinsey says in the video.

The man beside him rocks back and forth.

"I was more worried about him than myself," Kinsey told CNN affiliate WSVN-TV in Miami.

"As long as I've got my hands up, they're not gonna shoot me, that's what I'm thinking," Kinsey said. "Wow, was I wrong."

So far, Napoleon said, video of the shooting itself hasn't surfaced.

State takes over investigation

Reports of the North Miami shooting drew swift reactions on social media, with posts criticizing the officer who opened fire.

Kinsey's shooting comes after a pair of officer-involved shootings led to the deaths of two men, Alton Sterling and Philando Castile , kicking off a period of national unrest and putting the spotlight again on police use of force , particularly against black men. Kinsey also is black.

Protesters flooded the North Miami Police Department headquarters on Thursday, demanding answers for the shooting.

Eight law enforcement officers have since been killed in separate incidents in Dallas and Baton Rouge , Louisiana, targeted by gunmen who claimed they were reacting in part to incidents such as those that led to the deaths of Sterling and Castile.

The Florida Department of Law Enforcement is investigating the shooting.

"Bringing in an outside agency assures our commitment to transparency and objectivity in a very sensitive matter," Eugene said.

Prosecutors said they'll decide whether the officer should be charged after the state agency completes its investigation.

"They will provide us with their factual findings and conclusions," Miami-Dade State Attorney Katherine Fernandez Rundle said. "At that time, we will conduct our own investigation and review all of the evidence to determine whether the actions of the shooting officer constitute a criminal act that can be proven beyond and to the exclusion of every reasonable doubt."

'Why did you shoot me?'

Kinsey told WSVN he was stunned by the shooting, like when a mosquito bites unexpectedly.

"When he hit me, I'm like, I still got my hands in the air," he said.

"I'm like, 'Sir, why did you shoot me?' " Kinsey said he asked the officer.

"He said to me, 'I don't know.'"

North Miami police have said officers had "attempted to negotiate with the two men on the scene."

At some point, one of the officers discharged his weapon, police said. In a fact sheet released via social media, the police department said the officer involved in the shooting is a 30-year-old Hispanic male with four years on the job.

"I realize there may be questions about what happened on Monday night. You have questions. The community has questions. ... I, personally, have questions. I assure you, we'll get all the answers," the police chief told reporters Thursday.

'This is not supposed to be happening in North Miami'

Howard Simon, executive director of the American Civil Liberties Union of Florida, condemned the shooting: "Thankfully, Mr. Kinsey is alive and not more gravely injured -- but had the officer's weapon been pointed just a few degrees differently, this senseless incident could have been a much greater tragedy."

Simon called on law enforcement agencies to examine policies on the use of force and responses to people with mental health issues.

"Without changes in policy and improved training of officers, we will very likely see more needless shootings and deaths at the hands of police," he said in a statement.

A U.S. congresswoman whose district includes North Miami told reporters she was shocked by the video that shows the scene before the shooting.

"This is like a nightmare to me," Democratic Rep. Frederica Wilson said.

"When you shoot a man lying on the ground with his hands up, explaining to you the situation, and you shoot him anyway? Something's not right with this picture," she said.

The shooting she said, isn't typical of the city, which she described as a "melting pot."

"This is not supposed to be happening in North Miami. North Miami is a city where the police officers and the community gel," she said. "So many of our police officers come from the community (and) live in the community."

'He did everything he could possibly do'

A hospital spokeswoman said Kinsey is in good condition. His attorney called off a press conference with Kinsey on Thursday morning, saying his client was traumatized and speaking with a psychiatrist.

"The reality is that he believed ... that if you comply with the police and you lay on the ground with your hands up, and if you speak to them like my client was speaking to them, as Americans, we try to believe that that will not result in you getting shot," Napoleon said.

Now Kinsey, his attorney said, doesn't know what to tell his children.

"Physically, he will recover, but mentally, he felt like he did everything he could possibly do and that wasn't good enough," Napoleon said.

"You can't shoot unarmed people, period."