(Reuters) - Investigators are increasingly convinced that a teen gunman who killed three people at a weekend food festival in California acted on his own, but authorities said on Tuesday they remained largely in the dark about the motives for the shooting.
Police and FBI officials said at a news conference two days after the rampage in the northern California town of Gilroy that they still lacked any firm evidence about what spurred the suspect, Santino William Legan, 19, to launch his attack.
Legan was shot dead by police moments after he began firing with an assault-style rifle into a crowd attending the annual Gilroy Garlic Festival, a decades-old event celebrating produce farmed in the countryside of California's Santa Clara Valley southeast of San Jose.
"We continue to try to understand who the shooter is, what motivated him and whether he was aligned with any particular ideology," said Craig Fair, deputy special agent in charge of the FBI office in San Francisco.
An examination of material from his computers, cell phone and other digital media will hopefully provide a "holistic picture of (Legan), who he was in touch with, what sentiments and thoughts he shared with others, or catalogued for his own consumption," Fair said.
Authorities were initially looking into unconfirmed eyewitness accounts that Legan may have had an accomplice but Gilroy Police Chief Scot Smithee said on Tuesday that was appearing less likely.
"Our investigation is leading us more and more to believe that there was not a second person involved," Smithee said, although police had yet to rule it out altogether.
Surveillance video camera footage from several stores and other locations the gunman frequented in the hours before the attack showed no signs of any companions, he told reporters.
Smithee also said that in addition to the weapon used in the shooting, described by police as an "AK47-variant rifle," a shotgun was found in a search of Legan's car, which he left outside the park where the festival was held.
He said both weapons were purchased in Nevada, where Legan, originally from Gilroy, had been living with family members.
Police said they believe Legan made his way along a creek through a heavily wooded area adjacent to the festival, then cut through a fence to enter the festival grounds. A search of the creek area found a bag of ammunition, Smithee said.
WEAPONS OF 'MASS DESTRUCTION'
The Gilroy slayings added to an epidemic of gun violence in America that has fuelled a national debate pitting advocates of tighter controls on weapons against those who oppose further restrictions on the right to bear arms under the Second Amendment of the U.S. Constitution.
It is illegal to own military-style semi-automatic rifles in California. Governor Gavin Newsom used a visit to Gilroy after the shooting to decry what he said was the undermining of the state's gun control laws by looser regulations in nearby states and the federal government.
"You can't put borders up, speaking of borders, to a neighbouring state where you can buy this damn stuff legally," he told reporters after visiting survivors and their families on Monday. "I have no problem with the Second Amendment, you have a right to bear arms, but not weapons of goddamned mass destruction."
Several posts were published on what appeared to be Legan's Instagram account shortly before the attack, including one featuring a photograph of Sunday's festival. One urged people to read "Might is Right," an obscure racist and sexist tract written in the 19th century.
The post also railed against housing development in nearby Silicon Valley for what he called "hordes" of white people and Latinos with European ancestry. Legan described himself on his account as having Italian and Iranian ancestry.
Cellphone videos of the attack showed people fleeing past tents in panic as rapid-fire gunshots were heard.
The three people killed on Sunday were identified as Stephen Romero, 6; Keyla Salazar, 13, of San Jose, and Trevor Deon Irby, 25, of Romulus, New York, according to the Santa Clara County Medical Examiner-Coroner. A dozen others were injured.
Romero was remembered by relatives as a playful child, excited to start his first year at school.
Salazar was looking forward to her upcoming birthday and had asked her mother to buy her and her sister a golden retriever puppy, the San Francisco Chronicle reported.
Irby graduated from New York's Keuka College with a degree in biology in 2017 and was attending the festival with his girlfriend, according to the college and an online fundraiser.
At least five of the wounded were still in hospital late on Monday. A 12-year-old child and a 69-year-old were among those injured, officials said.
(Reporting by Steve Gorman in Los Angeles; Additional reporting by Jonathan Allen in New York; Editing by G Crosse and Paul Tait)