A father-of-one was unlawfully killed when he was restrained face-down on the pavement following an altercation at a railway station, an inquest has heard.
Jack Barnes, 29, from Hull, was held on the ground by four "customer service representatives" monitoring anti-social behaviour on the tram system at Manchester Victoria after he had earlier assaulted two of their colleagues.
Mr Barnes repeatedly said he could not breathe as he lay on the pavement in Deansgate in the city centre after he was caught following a 1,000 metre pursuit on the evening of October 11 2016, Manchester Coroner's Court was told.
One of the four men, a former police officer, took over the restraint position at one point and gripped Mr Barnes's neck and held his left arm behind his back as well as putting pressure on his back.
From bodycam footage worn by a colleague the former policeman was heard to say: "We're gonna put you out pal. You're all right" and then later added: "Right, if you struggle I will put you to sleep.
"It won't kill you.
"It won't kill you, but you will go to sleep for a while."
Mr Barnes did not continue to struggle or shout as the officer held him for a total of nine minutes and was heard to slur his words for a short period of time before he went on to have a cardiac arrest.
The inquest heard several minutes passed before anyone noticed he was not moving and he was turned over and his lips were seen to be blue.
Mr Barnes suffered a severe hypoxic brain injury and died in hospital on December 2 2016.
He had earlier taken an unknown quantity of the drug Spice before the incident at Manchester Victoria when his friends had got into an argument with one of the staff about allegedly consuming drugs on trams or platforms.
It led to Mr Barnes swinging his bag at two staff members before he was chased out of the station, the court was told.
HM senior coroner for Manchester, Nigel Meadows, noted his four pursuers were "overstimulated and aroused" and all had opportunities to phone the police during the course of the chase but did not so.
Concluding Mr Barnes was unlawfully killed, he said: "Jack's cardiac arrest was caused by a combination of factors involving the consumption of synthetic cannabinoids, the physical exertion of being chased for over 1,000 metres as well as an element of resistance to restraint in the initial stages but also the prolonged restraint itself and the unreasonable and excessive force used to do so."
He found the restraint "more than minimally, trivially or negligibly contributed" to the cardiac arrest.
Following the inquest Mr Barnes's mother Patricia Gerrard said: "From day one I have said that the people involved have needed to be prosecuted for what they did to Jack.
"If this had been the other way around, my Jack would have been sent to prison.
"I am certain of that.
"He should still be here with us and to see his beautiful daughter grow up."
Her lawyer, Lauren Dale, of Hudgell Solicitors: "This case is a reminder of the tragic consequences of security and other personnel seeking confrontation and using excessive force.
"In this case, the policy of the employer was to walk away yet they chased Jack for more than half a mile before pinning him to the ground and bluntly refused to listen to his requests to allow him to breathe more easily.
"Despite Jack being unconscious and not moving at all there was no sign of appropriate care being shown.
"Throughout the entire episode the response was wholly inappropriate to the incident which occurred and ultimately proved life-costing.
"We want to thank the coroner on behalf of Jack's family for the extremely thorough manner in which he has conducted this inquest, and given his findings, we will now be considering our next steps to seek justice for Jack."
Transport for Greater Manchester chief executive, Eamonn Boylan, said: "This was a tragic and deeply upsetting incident and we have worked closely with both Greater Manchester Police (GMP) and the Coroner's office to ensure the full facts surrounding Jack's death were thoroughly investigated.
"There were clear policies and training in place at the time of the incident, which those involved that evening completely disregarded."