Mr Ellis died on 3 March, while handcuffed and in police custody, from hypoxia and physical restraint, according to Rich O’Brien, from the Pierce County Medical Examiner’s office.
Hypoxia occurs when the body is deprived of an adequate oxygen supply, but Mr O’Brien added that heart disease and methamphetamine intoxication may have contributed to his death.
He was filmed being detained by then Minneapolis officer, Derek Chauvin, who knelt on his neck, while Mr Floyd repeatedly said “I can’t breathe.”
Ed Troyer, Pierce County Sheriff’s spokesman, told the Guardian that in early March, Mr Ellis approached officers in their vehicle at an intersection, and asked for them to help him.
Mr Troyer said that after Mr Ellis threw one of the officers to the ground, another wrestled him and put him in handcuffs, by the side of the road.
Mr Ellis then told them he couldn’t breathe, and the officers rolled him onto his side and called for an ambulance. He died around 40 minutes later.
Mr Troyer did not tell the outlet how Mr Ellis was restrained, or for how long the police officer wrestled him for.
Video footage of Mr Ellis’ arrest was published on Twitter on Thursday, by the Tacoma Action Collective, who said it was shot by an anonymous eye witness.
In the footage, two officers appeared to punch and kick Mr Ellis, as they restrained him and threw him to the ground. The collective claimed he was also tased.
The four officers involved in Mr Ellis’ arrest were put on administrative leave on Wednesday, while the Pierce County Sheriff’s Department investigates.
During a press conference on Thursday, Tacoma mayor, Victoria Woodards, said she had just reviewed the video evidence, and called for the officers involved to be fired and prosecuted for Mr Ellis’ death.
“In this moment, at this time, based on the information I know today, the officers’ actions we saw on this video tonight only confirmed that Manuel Ellis’ death was a homicide,” the mayor said.
“I am asking — no, I am telling you that I am going to call for several things, and the officers who committed this crime should be fired and prosecuted to the full extent of the law.”
Washington governor, Jay Inslee addressed the investigation during a news conference earlier in the week, but said all he knows about the case is that Mr Ellis died “under restraint.”
The governor added: “I know finding out the full circumstances of that event is a top priority for her and it is a top priority for me,” in reference to Ms Woodards.
“We know that we have to continue to push for de-escalation interactions between law enforcement and our community members.”
When asked if the officers should be charged with murder, Mr Inslee said that would be decided after a thorough investigation.
“I can’t render judgment on that right now because I virtually shared all that I know. So I know enough to know there has to be a very thorough investigation to lead wherever the evidence goes and people need to make appropriate decisions, and that could include criminal prosecutions.”
The governor added: “The situation in Tacoma will have to be investigated by an independent agency to make sure that it’s not tainted in some way.”
During a press conference in Tacoma, Washington, on Thursday, Mr Ellis’ mother, Marcia Carter said that after she found out about his death, she cried for “two months and 10 days, every day, all day.”
Ms Carter added: “Manny was taken from me, he was murdered,” and said her last words to her son were: “Remember, I love you.”
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