Three people have been killed and 15 injured after a gunman attacked a food festival in California. The gunman was shot dead by police shortly after he began firing, although police are investigating reports that a second suspect may still be at large. The Gilroy Garlic Festival was about to end for the weekend on Sunday evening, when shots were fired at the site. Six-year-old Stephen Romero is the first of the dead to be identified. His mother and grandmother were wounded. His father, Alberto Romero, told Mercury News that he was at home with his nine-year-old daughter when he got the panicked call from his wife. They had been playing in an inflatable bounce house at the time of the attack, she told him, when the boy was shot in the back. "I couldn't believe what was happening, that what she was saying was a lie, that maybe I was dreaming," said Mr Romero. "He was joyful, always wanted to play, always positive," he said, adding that the boy's mother has been placed in a medically induced coma after being shot in the stomach and her mother was being treated for a gunshot wound in the leg. It was the 246th mass shooting in the US this year, according to US tracking website Gun Violence Archive. The killer has been identified as 19-year-old Santino William Legan, according to CBS News. Witnesses said he was wearing camouflage, and used a rifle during the attack. Eyewitness Julissa Contreras told NBC that the attacker appeared to be "a white man in his early-30s". The lead guitarist of the group TinMan, who was performing on stage when the attack began, said he heard someone ask the shooter: "Why are you doing this?" Jack Vanbreen told the Associated Press that he heard the assailant respond: "Because I'm really angry".