Santino William Legan has been identified as the gunman. Photo / Supplied
The teen who opened fire at a food festival killing three people before he was fatally shot by police posted an ominous Instagram warning before the killing spree.
Authorities on Monday were searching for answers to why a 19-year-old opened fire on a popular food festival less than a mile from his parents' home in California, killing two children and another man, but believe many more people would have died if officers patrolling the event had not stopped the gunman so quickly.
Santino William Legan, 19, cut through a fence and appeared to randomly target people with an "assault-type rifle" Sunday afternoon, the end of the three-day Gilroy Garlic Festival that attracts about 100,000 people to the city known as the "Garlic Capital of the World," Gilroy Police Chief Scot Smithee said.
Police responded in less than a minute, and Legan turned his "AK-47-type" gun on the officers, Smithee said. Three officers fired back and killed Legan, who legally purchased the weapon in Nevada this month.
A second suspect "was involved in some way, we just don't know in what way," Smithee said, without giving further details. "We have no idea of a motive," he said.
Police recovered a rifle at the scene, Mr Smithee said.
An Instagram account bearing the suspect's name, created four days ago, posted two messages shortly before the attacks, including a reference to a white supremacist text.
One post was a photo of people walking around the Garlic Festival with the words "Ayyy garlic festival time Come get wasted on overpriced sh**." The other post, made about an hour later, showed a sign of Smokey Bear saying "Fire Danger High Today."
"Read Might is Right by Ragnar Redbeard," the caption said. "Why overcrowd towns and pave more open space to make room for hordes of mestizos and Silicon Valley white tw**s?"
A "mestizo" is a person of mixed descent, usually white and Hispanic, or white and American Indian, CNN reports. "Might is Right" is a book published in the late 1800s which has been described as a white supremacist text that promotes anarchy, vilifies Christianity and calls Jesus the "true Prince of Evil." The natural order, according to the book, is a world at war in which the strong must vanquish the weak, and white men must rule over those of colour.
Police said the gunman cut through a fence to evade metal detectors and other security at the festival's entrance.
He then appeared to randomly target people with an "assault-type rifle" at the end of the three-day festival which attracts about 100,000 people to the city known as the "Garlic Capital of the World".
Festival workers Cheryl Low and Candice Marquez told CBS both their bosses had been shot and are in hospital in a stable condition. They said the gunman opened fire randomly on the crowd.
"No, no. Just anybody. He was going back and forth," Ms Marquez said.
"It was random," said Low. "He shot one shot, then he put the clip in, and he just started moving shooting back and forth, walking towards our tent because that's where most of the people were in that area, and he started just shooting."
Footage uploaded to social media showed festival attendees scattering in fear and confusion as loud popping sounds could be heard in the background.
"What's going on?" a woman can be heard asking on one video. "Who'd shoot up a garlic festival?"
Evenny Reyes, 13, told the San Jose Mercury News that at first she thought the gunfire was fireworks but then saw someone with a wounded leg.
One video posted on Twitter showed a blood-spattered woman sitting in the back of a semi-trailer and telling a man she had been shot in the hand. Founded in 1979, the Gilroy Garlic Festival is an annual event run by volunteers and held outdoors at Christmas Hill Park.
Weapons of any kind are prohibited, according to the event's website, which also said anyone wearing clothing or paraphernalia indicating membership in a gang, including a motorcycle club, would be refused entry.
"I want to express my extreme shock and sadness about what's happened today," said Gilroy Mayor Roland Velasco, who described the attack as a "tragic and senseless crime."
FATHER'S GRIEF AFTER SIX-YEAR-OLD KILLED
The father of a six-year-old boy killed at the Gilroy Garlic Festival has described the shock and despair he felt after losing his son, saying the boy had his "whole life to live."
Alberto Romero told the San Jose Mercury News he was at home with his nine-year-old daughter when his wife phoned him to relay the devastating news that she had been shot, along with their son and her mother.
"I couldn't believe what was happening, that what she was saying was a lie, that maybe I was dreaming," the 33-year-old electrician said, in a video where he appears visibly distressed.
He went straight to St Louise hospital in Gilroy to see his son, who was in a critical condition.
"They told me he was in a critical condition and they were working on him. Five minutes later they told me that he was dead," Mr Romero said.
"There's nothing I really can do besides try to be with him until I can put him in his resting spot, wherever that is," his father, Alberto Romero, told NBC Bay Area.
"My son had his whole life to live and he was only 6. That's all I can say."
The young boy was one of two children killed at the festival, where a 13-year-old girl and a man were also murdered. At least 15 people were injured before the gunman was shot dead by police. His other grandmother, Maribel Romero, who was not at the festival, described him as "a really loving boy."
“My son had his whole life to live and he was only six,” said Alberto Romero. His son, Steven, was one of three people killed in yesterday’s shooting at a garlic festival in Gilroy, California.
"I want justice for my grandson," she said. A picture of Steven wearing a T-shirt that says "the birthday dude" was shared online by leaders calling for an end to gun violence.
2016 presidential candidate Hillary Clinton retweeted a comment from his father, Mr Romero and said "America cannot go on like this. For the sake of our kids, we have to change."