Former boxing champ Mike Tyson hits passenger in the head. Watch viral video

After a video of former heavyweight champ Mike Tyson hitting a fellow passenger surfaced on the internet, authorities on Thursday initiated an investigation into the incident.

The clip shows Tyson leaning over the back of his seat repeatedly striking the unidentified man in the head, drawing blood. The footage was first shared by TMZ, which said it was recorded on a Jet Blue plane bound for Florida.

Just before the incident, the passenger was seen standing over Tyson's seat and waving, while the boxer sits quietly.

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"Unfortunately, Mr. Tyson had an incident on a flight with an aggressive passenger who began harassing him and threw a water bottle at him while he was in his seat,” representatives for Tyson said in an email to The Associated Press.

Police said that the incident happened around 10 pm on Wednesday on a plane at the San Francisco airport's domestic terminal

"Officers arrived and detained two subjects that were believed to be involved in the incident. One subject was treated at the scene for non-life-threatening injuries. That subject provided minimal details of the incident and refused to cooperate further with the police investigation,” police said in a statement Thursday.

Both were released pending further investigation, the statement said.

Since Tyson, 55, retired from boxing, he has worked as an actor, podcaster and cannabis entrepreneur. He was in San Francisco for the annual 420 cannabis festival in Golden Gate Park, where he was promoting his cannabis brand Tyson 2.0, SFGate reported.

Tyson became the youngest heavyweight champion in history in 1987 at age 20. During his career he had 50 wins, 44 of them by knockout. In the 1990s Tyson served three years in prison after being convicted of rape. He has maintained his innocence in that case.