Khalifa was supposed to perform at the Sleep Train Amphitheatre as part of his ongoing Under the Influence of Music Tour, reported Ace Showbiz.
The victim has been identified as Eric Johnson of Oakland. The 38-year-old man was fatally shot backstage at the Shoreline Amphitheatre.
Gunshots were reportedly fired multiple times backstage after Khalifa, Young Jeezy, and other performers were wrapping a show in Mountain View, California.
Police rushed to the venue after receiving multiple calls about the gunshots. The victim was taken to a hospital, where he died. No one else was hurt. No arrest has been made as police has turned to social media asking concertgoers for photo or video that might provide clues.
"Due to a situation out of our control, UTIOM show is cancelled," Khalifa said on Twitter of his cancelled show.
"This was a senseless tragedy. Violence is never the answer. My prayers go out to the victim's family.
