Just before 11 a.m. Sunday, Hollister police responded to the Chevron on San Felipe Road for reports of a shooting.
They found three people with gunshot wounds and one victim who'd been assaulted.
Hollister firefighters treated the three gunshot victims at the scene but they eventually had to be air-lifted to Bay Area hospitals for further treatment.
Detectives were on scene for most of Sunday and are coordinating with multiple agencies to follow up on suspect leads.
Officers do not have a motive for the shooting. One source tells News Channel 5 that the "Boozefighters' club were gassing up to leave town, when a newer bike club approached and assaulted them at the Chevron."
At this time it appears the suspects and victims were bikers attending the rally. The violence occurred away from the rally but tempers between the parties may have spilled over into Sunday’s shooting.
Police tell NewsChannel 5 that patrol staff, and not officers specifically assigned to the rally, responded to the shooting.