US man caught on video punching himself in the face moments before his mugshot faces 18 years in prison for 'faking self-defence in racially motivated attack'

Brandon Killian, 29, didn't realise he was being filmed.

A US man is facing 18 years in prison after he was caught on camera punching himself in the face when a policeman left the room, after his arrest related to an earlier fight.

Brandon Killian, 29, is seen delivering blows to his own mug in the clip from June 22, just moments before he was due to pose for a mug shot, reports the Daily Mail.

He flinches as his own fists make contact above his cheeks.

In the footage from the police station in Shawnee, he responds to an officer who questions whether he is hurt: "This side of my face hurts, yes. The side of my face where, look right here, where I was first socked."

A man involved in the physical altercation, Jarric Carolina, spent weeks in hospital following the parking lot attack that was caught on surveillance footage.

His attorney Edward Maguire said he was lured "into the parking lot so they could tag team him and beat the living crud out of him.

You look at the kicks, you look at the hits, you look at the high fives, and you hear things like, 'you're dead and you're going to be dead.' I think that speaks to their motivation," the attorney previously said about the attack.

"He has trouble with basic functions, with learning how to walk again, trouble learning how to speak again, trouble recognizing family members."

The lawyer believes the beating was racially motivated.

Devan Johnson was also arrested for his part in the attack and is believed to be the one using the racist term.

"I hear the 'N' word being used, I hear you're dead, I hear those kind of things and that enough if you're motivated by hate to harm someone, to intimidate someone, if hate is your objective that is a hate crime," Carolina's lawyer said.

Multiple people are involved in the brawl – some of the camera view is shielded by cars – but it's believed Killian will face consequences for both that video and the one from inside the police station.

But one of the charges Killian faces, preparing false evidence, pertains to not the actual fight but his actions at the station.

In the video the cop asks him: "Were you rubbing on your face or something while we were gone?'"

With no idea he was being recorded the whole time, Killian replies: "A little bit, yeah."

It's believed Killian may have been trying to make his case stronger.

"Lying to the police and creating a false report will not be tolerated," DA Allan Grubb said on Monday. "Mr. Killian has been charged accordingly."

Carolina and his family were seen outside the court as they tried for the maximum sentence against Killian.

But Killian didn't show up to Pottawatomie County Courthouse as he was behind bars in Oklahoma County jail for another drugs violation incident.