The president of the San Francisco chapter of the Hells Angels motorcycle gang was gunned down after brawling with an unknown assailant, The San Francisco Chronicle reported.

Mark “Papa” Guardado, 46, was shot and killed Tuesday night outside a bar in San Francisco's Mission District, about a mile away from the gang’s clubhouse where he lived.

Witnesses told investigators that Guardado and the gunman struggled before the shooting and that the suspect fled on a motorcycle.

"His friends loved him," Guardado’s lawyer, Patrick Ciocca, told the Chronicle. "He really was an all-around good guy. There are hundreds, if not thousands, of people who are going to miss him dearly."

Police are exploring the possibility that a member of a rival motorcycle gang was responsible for the murder. No arrests have been made.

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