Witnesses said the victim is 52-year-old Steve Tausan.
No one else was injured.
Police were interviewing witnesses, but had no early leads.
"No one has been identified as a suspect, no one has been arrested," Garcia said.
A member of the rival Vagos motorcycle club is accused of killing Pettigrew on Sept. 23 in a Sparks, Nev., casino shooting that sent gamblers diving for cover. The mayor canceled a regional motorcycle rally as a result.
Saturday's shots were fired as thousands gathered for Pettigrew's funeral despite a heavy police presence.
Video from television stations showed dozens of police at the cemetery after the shooting, with sections blocked off with police tape.
One witness to the shooting, Valerie Hoffman said she was shocked.
"I've known Hells Angels and all the other groups for years and years and years, and there is a code of ethics," she said. "You never do anything at a funeral. I mean that is just completely abominable."
Hoffman said she left before the shooting and there were no early warning signs that violence would erupt.
"It's ridiculous! Especially in a memorial park," she said, "What were they thinking? There are code of ethics with all biker groups."
Garcia said the scene of the shooting "appeared to have been tampered with." He did not elaborate. Police did not say how many shots were fired.
No one else at the funeral was hurt.
Police and Santa Clara County sheriff's deputies were sent to guard the Hells Angels headquarters in San Jose, the San Jose Mercury News reported.