An eye-witness claims to have seen blood on the floor, following an altercation between Roy Keane and a football supporter.
The alleged assault happened at the Emirates Stadium before the full-time whistle when Arsenal beat Manchester United 3-1 on Sunday.
Keane and Richards were understood to be making their way to the pitch to carry out post-match duties for Sky Sports, who were broadcasting the Premier League fixture, when the incident happened.
A video circulated on social media appeared to show Richards trying to calm things down and appearing to restrain an unidentified man, who had allegedly aimed a headbutt at Keane and attempted to strike him on the chest and chin in front of onlookers.
“The incident occurred shortly before the 90th-minute mark in the Highbury Bar for platinum members,” an eye witness told The Daily Express.
“The fan seemingly tried to head-butt Roy Keane. I then saw a mark between his eyebrows. Micah Richards stepped in and pushed the fan back against the door. I heard the altercation and I was shocked to see the individuals involved.
“Richards was very forceful at keeping the fan from attacking Keane and neither their security nor the door security could split the two apart. Keane was asking nearby staff to call the police.
“Additional security was called in and Richards and Keane followed until the fan was escorted downstairs via the escalator out of the building.
“Presumably, Keane and Richards then returned to their Sky Sports duties via the exit that they came in through next to where the video is shown.
“Afterwards, we noticed a small amount of blood on the floor on the route where the fan was led out. Seems like Micah Richards was acting as Roy Keane’s bodyguard.”
The Metropolitan Police confirmed they were looking into the incident. and both Keane and Richards have provided them with statements.
“Police are investigating following an assault that is alleged to have occurred at the Emirates Stadium during an Arsenal v Manchester United match on Sunday, 3 September,” a statement from the capital’s force said.
A spokesperson for Sky Sports said: “We understand the police are investigating an alleged assault by a member of the public immediately preceding the footage circulating on social media. In the footage seen, Micah Richards was acting to diffuse a situation.”
Arsenal won the game thanks to late goals from Declan Rice and Gabriel Jesus.
Marcus Rashford had given Manchester United the lead on 27 minutes but Martin Odegaard equalised a minute later.
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