D.A.: S.F. Muni killer was 'hunting' for victims

San Francisco prosecutors filed murder and assault charges Friday against a 30-year-old man accused of shooting a college student to death as he stepped off a Muni train, saying the suspect was hunting human prey before settling upon his final victim.

District Attorney George Gascón also said that just before shooting San Francisco State student Justin Valdez, 20, on Monday night near Valdez's home, the suspect brandished his gun brazenly on the light-rail car, with little effect.

"On the surveillance video we have, everyone is looking at their cell phones and personal devices, and nobody notices," said Gascón. He said he found that "concerning."

Nikhom Thephakaysone of San Francisco made his first court appearance Friday, but he did not enter a plea. Nor did not look at his family.

"We have no idea how this happened - we are shocked," the suspect's stepfather, who gave his name only as Tei, told The Chronicle.

Gascón said that prior to shooting Valdez with a .45-caliber pistol, the suspect had waved his gun in front of a restaurant and then threatened to shoot a passenger on a different train. Both actions happened near the Muni stop outside San Francisco State where he boarded the train Valdez was on, Gascón said.

"This individual went out hunting that night, and unfortunately for the victim, he was in the wrong place at the wrong time," Gascón said. "This was a wanton killing. There was absolutely no reason for this other than pure violence."

Thephakaysone was charged with murder, assault for the earlier Muni threat, and possession of an illegal assault rifle allegedly found at his house.