Teachers had been warned about Nikolas Cruz, the teenager who is accused of killing 17 people and injuring dozens more at his former school in Florida.
Jim Gard, a maths teacher at Marjory Stoneman Douglas High School, told the Miami Herald that school authorities had emailed teachers about Cruz’s behaviour and warned them that Cruz was not to be allowed on campus with a backpack.
Gard explained “There were problems with him last year threatening students, and I guess he was asked to leave campus.”
The school have not disclosed why Cruz was expelled from the school, but students told reporters it was because of a fight with his ex-girlfriend’s new boyfriend.
Cruz has been charged with 17 counts of premeditated murder following the deadly shooting, the worst at a US school since 2012. Several people remain in hospital, where doctors have said they are in a “critical condition”.
Police say they received “no warnings” about a possible attack at the school or the threat Cruz posed to the safety of students and teachers.
At 14:30 local time (19:30 GMT) on Wednesday, Cruz is believed to have deliberately pulled the fire alarm at Marjory Stoneman Douglas High School in Parkland, Florida in an attempt to flush the students out of their classrooms.
The alarm caused a number of teachers and students to leave their classrooms and make their way through the halls of the school towards the emergency exits.
Witnesses say Cruz, wearing a gas mask, was waiting in the corridor and set off a series of smoke grenades before opening fire on students and teachers alike with an AR-15 semi-automatic assault rifle.
Upon hearing the shots, students and teachers rushed back into their classrooms, barricaded the doors, and attempted to hide in cupboards and beneath desks.
As armed police arrived on the scene and started to evacuate students, Cruz is believed to have tried to blend in with the fearful students, but was arrested several miles away from the school and is now in police custody.