GILROY, Calif. _ As authorities try to determine the motive for the Gilroy Garlic Festival attack, investigators believe their best shot is through the digital footprint of 19-year-old Santino William Legan, according to law enforcement sources.
Detectives have been looking through his social media, electronic devices and computer hardware but are still struggling to understand why he opened fire, killing three and leaving 15 hurt Sunday night at the famed food festival, the sources said.
"Our preeminent and principal concern is motivation, ideological leanings and was he affiliated with anyone or any group," said Craig Fair, FBI deputy special agent in charge of counterintelligence at the San Francisco office.
During the attack, someone shouted a pivotal question as he unleashed round after round from his AK-47 style assault rifle: why are you doing this?" He simply replied: "Because I am really angry!"
"Everyone wants to know the answer: Why?" Gilroy Police Chief Scot Smithee said. "If there's any affiliation with other people, or groups of people, that could potentially pose a threat in the future, that all plays in."
The digital footprint in the case of the San Bernardino terror attacks that left 14 dead and 22 wounded yielded a considerable history of aspiring to commit a holy war on America.
The killers in that case where so aware of their digital footprint they tossed away their laptop's hard drive. But in the case of the 2017 Las Vegas mass shooting that claimed 58 lives, Las Vegas police and the FBI _ despite a year of investigation _ were unable to ascribe a motive for Stephen Paddock's rampage during the Route 91 Harvest music festival.
In letting Gilroy police be the lead agency, the FBI has already eliminated the prospect that Legan's actions on their face were terrorist in nature as federal law requires for the bureau to lead such investigations.
Smithee, asked whether the victims were targeted, said Monday that it seemed "random." But he cautioned that the motive remains unknown.
FBI spokeswoman Katherine Zackel said agents are continuing to gather evidence at the crime scene, which is extensive. "It is a very large and complex scene," she explained, noting that it could take several days. In the past, the bureau has flown evidence back to its Virginia lab for examination by a plethora of forensic experts.
Before the attack, he posted a photo on Instagram with the caption, "Ayyy garlic festival time come get wasted on overpriced (expletive)."
He also posted a photo of a Smokey Bear sign warning about fire danger, with a caption instructing people to read an obscure novel glorified by white supremacists, "Might Is Right," published under the pseudonym Ragnar Redbeard. In his profile, which has since been deleted, Legan identified himself as being of Italian and Iranian descent.
The book, published in 1890, includes discredited principles related to social Darwinism that have been used to justify racism, slavery and colonialism, said Brian Levin, director of Cal State San Bernardino's Center for the Study of Hate and Extremism.
"The notion that people of color are biologically inferior is a key tenet of this book, and that biological determinism, the Darwinian view of the world, justifies aggression against diverse people and vulnerable people," Levin said.
The famed festival was winding down when authorities allege that Legan crept past a creek and cut through a fence, bypassing entrance security, while armed with an AK-47-style rifle.
Soon after, he began spraying attendees with gunfire, authorities said, claiming three lives and wounding a dozen people. Within a minute, Legan was shot and killed as three police officers arrived and fired at him with their handguns.
