A black man has died after pleading that he could not breathe as a white police officer kneeled on his neck during an arrest.
Footage of the restraint was shared widely online after a bystander filmed the officer pinning the shirtless man to the ground in Minneapolis, Minnesota.
Four police officers involved in the arrest have since been fired, with Minneapolis Mayor Jacob Frey saying: “This is the right call.”
The FBI and state agents are investigating after the death on Monday night.
The suspect can be heard saying “please, please, I can’t breathe” in the footage.
He then adds: “My stomach hurts. My neck hurts. Everything hurts.”
Onlookers can be heard urging the police officer kneeling on the man to get off him, with one pointing out that the suspect was not resisting arrest.
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Another claimed that the policeman appeared to be enjoying the altercation.
The man who died has been identified as George Floyd by Ben Crump, a prominent civil rights and personal injury lawyer – who said he had been hired by Mr Floyd’s family.
Following the incident, Minneapolis Police Chief Medaria Arradondo said: “We clearly have policies in place regarding placing someone under control.”
Mr Arradondo said looking at what happened and how those policies apply “will be part of the full investigation we’ll do internally”.
Officers had been called at about 8pm local time (2am UK time) to a report of forgery at a business, police spokesman John Elder said.
Police found Mr Floyd, believed to be in his 40s, matching the suspect’s description in his car.
Mr Elder said in a statement: “He was ordered to step out from his car. After he got out, he physically resisted officers.
“Officers were able to get the suspect into handcuffs and noted he appeared to be suffering medical distress.”
Police said Mr Floyd – who they did not name – was taken by ambulance to Hennepin County Medical Centre where he died a short time later.
The names of the fired officers have not been released.
The Minnesota Bureau of Criminal Apprehension (BCA) has joined the FBI in its investigation.
All body camera footage has been turned over to the BCA, which investigates most police shootings and in-custody deaths.
Nekima Levy-Armstrong, a prominent local activist, said watching the footage that was shared on social media made her “sick to her stomach”.
She told the Star Tribune in Minnesota: “Whatever the man may have done should not have ended in a death sentence.
“What started as an alleged economic incident once again turned deadly for a black man.”
Ms Levy-Armstrong said it reminded her of the case of Eric Garner, an unarmed New York man who died after he was placed in a chokehold by police in 2014.
He had pleaded for his life and said he could not breathe during the incident.
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A grand jury later decided against indicting the officers involved, sparking protests around the country.
Mr Frey has urged those who might protest to take precautions amid the coronavirus outbreak on Tuesday.
He said there is a “need to make sure everyone voicing their opinion is staying safe,” and he asked potential protesters to practice social distancing.
Mr Frey said: “If you’re sad, I get it, if you’re angry, that makes complete sense, if you feel the need to protest, of course, we want to make sure people are able to express themselves.
“There is another danger out there right now, which is COVID-19.”
Police in Minneapolis have come under scrutiny in recent years for deadly run-ins with citizens.
Jamar Clark, a 24-year-old black man, was shot in the head and died in 2015 after a confrontation with two white officers responding to a reported assault.
A county prosecutor declined to prosecute the officers, saying Mr Clark was struggling for one of the officers’ gun when he was shot.
Meanwhile, a white woman, Justine Rusczcyk Damond, died in 2017 when she was shot in the stomach by a Minneapolis officer responding to her 911 call.
That officer, who is black, was convicted of manslaughter and murder and is serving a 12-year prison sentence.