PHOENIX -- A gun used by a Phoenix teen to kill his ex-girlfriend and then himself, belonged to his older brother.
"It (the gun) was legally possessed and in fact, [it] was in a locked bedroom," said Phoenix Police Sgt. Tommy Thompson. "It appears that [the boy] broke a window to break into that room from the outside to take that gun."
Phoenix police said they responded to a 911 call of a shooting around noon Friday at a house near 39th Drive and Happy Valley Road. Witnesses saw the boy, 15, chase the girl, 16, heard a shot and a friend of the couple saw the boy take his own life.
Police say it's still unclear what set the boy off. Both victims were students at Sandra Day O'Connor High School.
The Associated Press contributed to this report.