San Francisco police allege that on September 23, Nikhom Thephakaysone shot and killed college student Justin Valdez while they were getting off the train. The randomness of the alleged murder is made more troubling, according to investigators, because of video evidence that demonstrates that although Thephakaysone openly brandished his .45-caliber pistol, commuters were too engrossed in their smartphones to notice. “These weren’t concealed movements — the gun is very clear,” San Francisco District Attorney George Gascón told the San Francisco Chronicle.