Prosecutors said Wednesday that singer D4vd fatally stabbed 14-year-old Celeste Rivas Hernandez multiple times before dismembering her body in his garage with chainsaws. In a court filing, the Los Angeles County District Attorney’s Office outlined what it said the evidence would show, offering the first detailed account of the alleged killing and efforts to cut apart the victim’s body and conceal evidence. According to the filing, D4vd, whose legal name is David Burke, met Rivas Hernandez when she was 11 and began sexually abusing her when she was 13 and he was 18. Prosecutors claim he killed her after she threatened to expose the relationship. “Knowing he had to silence the victim before she ruined his music career as she had threatened, very soon after her arrival at his home, defendant stabbed the victim to death multiple times and stood by while she bled out,” the filing said.…