A police officer appears to repeatedly knee a suspect that fellow cops had pinned down in disturbing footage.
Steven Walker was walking home when he saw detectives arrive at a suspected armed robbery at a shop in Bolton, Greater Manchester.
The dad-of-two filmed about six officers apprehending three men last Thursday.
His footage shows a police car come skidding to a halt halt to join two vans.
Three officers were attempting to hold down one suspect, while the other two men each lay on the floor supervised by cops.
One struggling suspect screams and cries while he claims officers were ‘snapping his arm’.
One of the poliuce holding him down then appears to throw at knee him at least five times to his head or back .
Mr Walker, a 29-year-old building engineer, shared the footage online in a bid to highlight what he calls ‘police brutality’.
Greater Manchester Police confirmed they were aware of the video circulating but had not received a formal complaint.
Mr Walker, from Bolton, said: “It’s shocking. It’s police brutality. One of the lads was covered in blood and the three lads were initially apprehended but that force was just excessive.
“When that other officer started kneeing him in the head I just couldn’t believe it.
“The guy on the floor was shouting things like ‘I can’t breathe, I can’t breathe’.
“Now, I know the police have a job to do and people can get a bit ‘pasty’, but punching someone and kneeing them five times is just mad.
“Six officers were on three lads – that’s clearly excessive. I think he was trying to make him turn over.”
Mr Walker estimates around 10 police were on scene by the time all three suspects were apprehended.
He believes the police were responding to a call that a shop keeper had been threatened with a hammer.
In the video the police officer appears to demand the onlookers move along, But Mr Walker kept filming.
He posted the video on social media and the video quickly racked up almost 20,000 views.
Mr Walker said: “One or two people thought the police should have been doing this, others thought they shouldn’t.”
A Greater Manchester Police spokesman said: “We have been made aware of a video circulating on social media and are currently reviewing the footage, while also speaking to response officers who attended the incident to get a full picture of the circumstances.
“We are currently not aware of a formal complaint but will continue to monitor this.”