New Delhi: Police identified the 19-year-old gunman as Nikolas Cruz, who previously attended the school and was expelled for unspecified disciplinary reasons, Broward County Sheriff Scott Israel said at a news briefing hours later.

The gunman returned to the Florida high school where he had once been expelled for disciplinary problems and opened fire with an assault-style rifle on Wednesday, killing 17 people and injuring more than a dozen others before he was arrested, authorities said.