At least one gunman opened fire yesterday at Northern California’s Gilroy Garlic Festival, killing at least three and injuring 15, before being fatally shot by police stationed nearby who responded in less than a minute after the initial shot was fired, a police official said.

The shooting rampage began at 5:41 p.m. on the north side of the festival, Chief of Police Scot Smithee said at a press conference.

Smithee said the gunman gained access to the festival by cutting through a fence near a creek area. He said some witnesses reported a second suspect, but police could not immediately confirm those reports.

A manhunt was underway to find a possible second suspect. It was not immediately clear if there were two shooters.

A 6-year-old boy, Steven Romero, was among the victims.

Personal videos posted to Twitter appeared to show large crowds evacuating the festival. Many witnesses said the shots sounded like fireworks and there was confusion. The first shots were fired near an amphitheater, one witness said.