Watch the awkward moment a boxer's uncle punches an opponent

Dirrell's uncle Leon Lawson was furious after Uzcategui landed a left hook that flattened Dirrell at the end of the eighth round, a blow ruled after the bell and following an early warning for punching after the bell.

The South American was disqualified for that shot and Dirrell named the winner.

But Dirrell's uncle, Lawson, entered the ring in the moments after the finish and sucker punched Uzcategui with a left to the jaw.

Telecasters Showtime said police were searching for Lawson to arrest him but he apparently had departed the venue.

Police also spoke with Dirrell and were reviewing security camera video footage regarding a pre-fight incident involving Dirrell.

Dirrell apologized for his uncle after his bout and Russell apologized to fans for the incident after his victory.