A cache of assault rifles and other weapons were found at the home of a suspect arrested for an apparently unprovoked fatal shooting in San Francisco's Ingleside Heights neighborhood on Monday, the city's police chief said today.

Nikhom Thephakaysone, 30, was arrested on Tuesday outside his home in the city's Oceanview neighborhood on suspicion of the fatal shooting of 20-year-old Justin Valdez at about 9:50 p.m. Monday near Randolph and Bright streets.

Valdez was shot in the back as he was getting off a San Francisco Municipal Railway M-Ocean View light-rail vehicle, police Chief Greg Suhr said at a news conference this afternoon.

Investigators found surveillance footage from the Muni vehicle and were eventually able to identify Thephakaysone as the suspect.

When they went to his home in the 200 block of Lobos Street and arrested Thephakaysone, police found two assault rifles, knives, survival gear and about $20,000 in cash in his possession, Suhr said.

Suhr said the suspect lived at the home with his mother, stepfather and sister.

The chief said he did not know what Thephakaysone may have had planned with the various weapons, which included a Ruger .223-caliber rifle and a M+M M10-762 rifle.

"You'd be hard-pressed to understand why somebody would possess this sort of firepower," he said. "We're just glad nothing played out other than it did" with the death of Valdez.

The chief said both the victim and the suspect were students at San Francisco State University but did not know each other.

He said they both got onto the Muni vehicle at 19th and Holloway avenues but did not interact while onboard.

The Muni surveillance video captured Thephakaysone allegedly pulling out a .45-caliber weapon a couple of times then putting it away, and apparently no one onboard saw the firearm, Suhr said.

Police found the gun at the scene after Valdez was shot, he said.

Suhr said Thephakaysone apparently also pulled out the gun and threatened two other people prior to getting onto the Muni train, but no one called police to report either incident.

"That has to be a 911 call immediately," he said. "This could well have been averted."

Valdez's sister attended this afternoon's news conference but did not speak to reporters.

Suhr said the victim's family is asking for the public's help in raising money to transport him back to Southern California to be buried.

Valdez, who lived in San Francisco, grew up in Garden Grove in Southern California.

People interested in donating can visit www.giveforward.com/fundraiser/c253/justin-valdez-memorial-fund.

SFSU officials said Valdez was a sophomore at the school and had not yet declared a major.

School spokeswoman Ellen Griffin said Thephakaysone was admitted to SFSU as a transfer student in 2008 as a dietetics major and was a full-time student for a year, but has since been taking classes off-and-on, including this semester.

District attorney's office spokesman Alex Bastian said Thephakaysone is being charged with murder and is scheduled to be arraigned on Friday afternoon in San Francisco Superior Court.


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