Cruz was identified as a former student of the high school who was asked to leave after threatening a student in Spring 2017. He is currently 19 years old.
According to math teacher Jim Gard, who had Cruz as a student in the previous school year, teachers were instructed to not allow Cruz on school grounds following his departure.
"We were told last year that he wasn't allowed on campus with a backpack on him," Gard told The Miami Herald. "There were problems with him last year threatening students, and I guess he was asked to leave campus."
Cruz reportedly began shooting around 2:30 p.m. on Wednesday, minutes before the school day's dismissal. Using an AR-15 rifle, Cruz reportedly pulled the school's fire alarm then opened fire as kids began filing out of classrooms.
"We all thought it was a fire drill because we had one previously today," a student told Fox 6. "And we thought it was, so no one was that nervous, but then word started going around that it was shots and not just, like, something else, everyone just started running towards the canal."
One student managed to live tweet the shooting, while others posted videos to social media from inside classrooms. Police and SWAT arrived on the scene and helped many of the students out of the building, while others quickly fled on foot without being seen by Cruz.
Broward County Sheriff Scott Israel confirmed at least 17 are dead as a result of the shooting, though 12 more are currently receiving treatment for injuries at medical facilities.
Cruz was arrested at approximately 3:11 p.m. at a townhouse in Pelican Pointe at Wyndham Lakes in Coral Springs, Florida.
One student told WSBTV that, while he was attending the school, many students joked that Cruz would one day commit an act of violence at the school.
"Honestly, a lot of people were saying that it was going to be him," the student said. "A lot of kids threw around jokes like that, saying 'this is the one that's going to shoot up the school,' but it turns out everyone predicted it. That's crazy."
Cruz reportedly had a pair of Instagram accounts, where he posted a series of photos displaying an assortment of knives and guns.
Photo Credit: Twitter / @S_wayne1