No-one was prosecuted over the death of a man who was restrained in the street by public transport workers despite the case being reviewed three times.
Jack Barnes, 29, shouted "I can't breathe" repeatedly while being restrained in a street in Manchester.
A coroner ruled on Friday that Mr Barnes had been unlawfully killed.
Four men were arrested following his death but the Crown Prosecution Service (CPS) said there was not sufficient evidence to prosecute.
The CPS said it had "carefully considered" the evidence provided by police and the same decision was reached after two further reviews, which were carried out under the Victims' Right to Review Scheme following requests from the family.
The Mayor of Greater Manchester, Andy Burnham, has described the bodycam footage as "one of the most distressing things you could see".
"What we've got to do is look carefully at the coroner's ruling and ensure all of what he is saying is understood and that action is taken to prevent any possibility of any repeat of anything of this kind," he said.
The inquest heard father-of-one Mr Barnes, from Hull, became aggressive after being confronted by a Metrolink customer service representative (CSR) in October 2016 before he and a friend ran off.
Metrolink's policy was that their representatives should walk away from such encounters, alerting the police if necessary.
But four workers - Paul Fogarty, Brian Gartside, Matthews Sellers and Stephen Rowlands - decided to chase the fleeing pair, two on foot and two in a taxi.
Manchester Coroner's Court heard after a nine-minute chase across almost a mile of the city centre, Mr Barnes was caught by Mr Gartside and bundled to the ground on Deansgate.
Bodycam footage from a camera worn by Mr Sellers showed that within moments of being caught, while being held down with his left cheek on the pavement, Mr Barnes asked for help and shouted out: "I can't breathe."
Over the course of about 90 seconds, Mr Barnes said he was struggling to breathe on eight separate occasions.
Just before the camera moved away to focus on Mr Barnes' friend, Mr Rowlands was recorded telling him: "If you struggle, I will put you to sleep.
"It won't kill you but you will go to sleep for a while."
The inquest heard Mr Barnes suffered a cardiac arrest and died seven weeks later on 2 December 2016.
Mr Rowlands declined to speak to the BBC when approached for comment.
Concluding his death was unlawful, coroner Nigel Meadows said the workers' actions amounted to manslaughter and the exertion of the chase and the pressure on Mr Barnes's neck more than minimally contributed to the heart attack.
Speaking after the hearing, Mr Barnes's mother Tricia Gerrard told the BBC the men had "hunted him down like an animal".
She said the family refused to believe he had attacked the CSRs, as at "any sign of trouble, any sign of violence, he'd run".