“We called the fighter and his lawyer and said, what’s going on? There’s some weird betting action going on in your fight,” White said.

“Are you injured? Do you owe anybody money? Has anybody approached you? The kid said, ‘No, absolutely not. I’m going to kill this guy’. So we said OK.

“The fight plays out – and first-round finish by rear-naked choke. Literally, the first thing we did was call the FBI.”

Betting company Caesars Sportsbook announced it would refund bets on the fight shortly after it ended.

Earlier this week, the UFC issued a statement saying it was “conducting a thorough review of the facts surrounding the Dulgarian vs del Valle bout on Saturday”.

“We take these allegations very seriously and along with the health and safety of our fighters, nothing is more important than the integrity of our sport,” the statement added.

Dulgarian’s coach Marc Montoya has denied any knowledge of foul play around the fight.

“We have nothing to do with any of the allegations being brought upon us,” he told the The Ariel Helwani Show.

“I’ve actually never even placed a sports bet in my entire life – I couldn’t tell you how to do it.

“This is my life’s work. I would never, for any amount of money, sell my integrity or my word – because in life, that’s all you have.”