A 16-year-old boy who shot five fellow students at Saugus High School Thursday, killing two of them before turning the gun on himself, died at a hospital Friday afternoon, sheriff’s officials said.

Nathaniel Tennosuke Berhow was pronounced dead just after 3:30 p.m., according to Sgt. Jennifer Roth of the Los Angeles County Sheriff’s Department Information Bureau. Berhow, a junior at the high school who officials said carried out the attack on his 16th birthday, had been hospitalized in critical condition since Thursday morning’s shooting. Officials said his mother was present at the time of his death. Meanwhile, Los Angeles County coroner’s officials on Friday identified the two student victims who died in the attack as 14-year-old Dominic Blackwell and 15-year-old Gracie Anne Muehlberger. A 14-year-old girl and 15-year-old girl remained hospitalized in good to fair condition Friday. Another 14-year-old boy wounded in the shooting was treated at a hospital and released on Thursday. A motive in the mass shooting has not been determined by investigators. The killer left no suicide note.