New video is thought to show the moments before a police officer apparently kicked and stamped on the head of a man lying on the ground at Manchester Airport on Tuesday.
In the video, police appear to attempt to restrain one man, before a second man tries to intervene and a fight breaks out.
A constable was suspended after a different clip of the same incident circulated online.
The officer is facing criminal investigation for assault by the Independent Office for Police Conduct (IOPC) and has been served with a disciplinary notice for potential gross misconduct.
Greater Manchester Police (GMP) said the officer’s actions had come after he and other colleagues were “violently attacked” in a car park in Terminal 2 at about 20:30 BST on Tuesday.
The new footage, exclusively obtained by Manchester Evening News, appears to show three police officers attempting to detain a man, before another man approaches them and tries to intervene.
The BBC has not independently verified the source of this video.
After the second man’s intervention, a fight breaks out and punches are thrown.
The first man punches two officers to the ground, while another officer points a taser at the second man.
As the first man wrestles with a third officer, another officer appears to deploy a taser and the pair fall to the ground.
The man then lies face down with his arms fixed by his sides as the officer gets up.
An older woman, who falls earlier in the video, crawls over to the man, who is lying mostly still.
This is when an officer apparently kicks the man on the ground in the head.
The new footage ends here, but the original video appears to show that the officer then stamps on the man’s head.
BBC Verify analysis of five social media videos of the incident suggests the violence did not end here.
Another video appears to show the same officer approaching another man, stamping on his thigh, and hitting him on the back of the head with a taser.
Another officer appears to pepper-spray bystanders who were filming the incident.
The newest video is not included in the Verify coverage.
A crowd of people protested outside a police station in Greater Manchester on Thursday, accusing the police of institutional racism.
The family of the man who was stamped on has appealed for “calm in all the communities”, according to Rochdale MP Paul Waugh, who spoke with them after the incident.
He told BBC Breakfast the family were “acutely aware” there were “extremists of all sides who are keen to hijack this incident for their own ends”.
He said the “strong message” the family wanted to give is that they have “no political agenda whatsoever”.
A police spokesman said there had been a “clear risk” the firearms officers could have had their weapons taken from them, and three officers had been taken to hospital, one with a broken nose.
Four men, aged 19, 25, 28 and 31, were arrested in the aftermath on suspicion of affray and assault, and later bailed.
The force said it understood the “deep concerns” that had been “widely raised” over the footage.
Greater Manchester Mayor Andy Burnham urged people not to rush to judgement, saying the incident was a “complicated situation with two sides to it”.
“It is frustrating that we have not been able to put more video into the public domain but that is because this is a live investigation,” he said.
“People now need to step back and allow the IOPC’s criminal investigation into the officer’s conduct to move forward, alongside the parallel GMP investigation into other potential offences, so that a complete picture can be presented.”
Human rights lawyer Aamer Anwar told BBC Newsnight he was disappointed that leading politicians, including Mr Burnham, had asked people to consider the context to the incident.
There was “no justification” for a police officer to act this way, he said, adding that the context was “irrelevant”.
