Mark "Papa" Guardado, 45, died at San Francisco General Hospital after he was shot Tuesday night in the Mission District, the San Francisco Chronicle reported. Police said the killer escaped by motorcycle and are investigating the possibility that he was a member of the Mongols, another biker gang.

"They had a wrestling match first," said Lt. Mike Stasko of the San Francisco Police homicide detail. "The guy shot him, and he got on his motorcycle and left."

Guardado served a prison sentence in Massachusetts in the 1990s but had no convictions in California, police said. At the time of his death, he was under indictment for an assault on a patron at a bar in Petaluma, north of San Francisco.

Sgt. Jim Stephenson of the Petaluma police said that Guardado initiated what turned into a mass beating for "no reason." But Guardado's lawyer holds a different view of his late client.

"His friends loved him," 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."