Updated

San Francisco police are investigating the death of a Giants fan who was seriously injured during the World Series victory celebration.

Officer Gordon Shyy says 37-year-old Sean Moffitt died of head trauma at San Francisco General Hospital on Oct. 30, two days after he was hurt during street celebrations in the Haight-Ashbury neighborhood.

Police say Moffitt's death is considered suspicious and police are trying to determine how he died.

Shyy says after the celebration, Moffitt told his roommate he had been assaulted by four men with a metal pipe, but investigators weren't able to interview Moffitt and no one reported an assault to police.

The San Francisco Chronicle reports that investigators are looking for possible witnesses and surveillance-video footage that may show what happened.