A police officer knocked out a former prisoner in brutal fashion during a blockbuster match-up at BKFC's latest event.

BKFC, the bare knuckle fighting promotion which recently staged a war between former UFC stars Darren Till and Yoel Romero, had its latest show at the Prudential Center in Newark, New Jersey.

It was headlined by the bout between Jamel Herring and John Dodson, with the BKFC bantamweight title on the line.

Former UFC star apologised for brutal knockout

But there was also a notable match-up on the undercard as Jimmy Rivera, a current serving police officer, squared off against a man who has served time 12 years behind bars in Brandon Meyer.

Meyer was 12 years old when he went on probation as a juvenile, his friend telling cops that he broke into an ice machine.

The 43-year-old, whose stepdad was sentenced to life in prison for murder, spent more than a decade in federal prison but transitioned into MMA after having a fight at a party, which ended up then taking place in the park with 50 or 60 people present.

The dynamic between the two was mentioned at the weigh-in, where interviewer Jake Noeker brought up the different sides of the law.

That led to Rivera coming up with a memorable line when he said, “He gets to beat me up and not get arrested for it, so it’s a win-win”.

But it was Rivera who scored the victory 46 seconds into the fourth as a combination of deadly punches slept Meyer, who dropped to the deck as the referee waved off the contest.

The sickening knockout prompted an apology from Rivera, who is 4-1 in BKFC.

Speaking afterwards, he said: "It's unbelievable.Thank you to Jersey, my friends, my family - everybody that came out to support me. This is a huge arena and it's packed out.

"I feel really bad because his kids were in his corner and the shot I landed was a shot. I apologised to them and said sorry but I was looking for that one shot.

"I took my time. Surprisingly he wasn't engaging as much. I had to be patient."

How former UFC star became police officer

Rivera competed in UFC's bantamweight division, squaring off against former champions Petr Yan and Aljamain Sterling. He then graduated from the New Jersey Police Academy in 2023 and works for Elmwood Park Police Department.

At first, 'El Terror' tried his hand at dispatch during the COVID-19 pandemic and later ended giving jiu-jitsu lessons to officers.

His need to be busy is what prompted him to join the force late in his life.

"I won’t say I have ADHD, but I can’t stop," he told MMA Junkie.

"I always have to work. I’ve always got to do something. I’m all about the grinding. … It’s also very bad mentally, to not do anything. You see people who retire and they don’t do anything. They end up getting right back into it or they mentally degrade and don’t look the best anymore,”