9USA TODAY)  Seventeen people are dead after a shooting at a south Florida high school on Wednesday. The man suspected has been identified as 19-year-old Nikolas Cruz.

Here’s what we know about him:

Cruz is a former student of Marjory Stoneman Douglas High School, where the shooting happened. He was expelled due to disciplinary issues.

Cruz had multiple magazines and one AR-15 rifle.

Cruz started shooting outside and then went inside the school.

Law enforcement has been looking at his social media. They say “Some of the things … are very, very disturbing.”

According to USA Today, teachers and former students say Cruz had an angry disposition that led to him being expelled and flagged as a danger on school grounds. He had previously attracted so much concern that school administrators banned him from campus, said Jim Gard, a math teacher at Marjory Stoneman Douglas High School in Parkland, USA Today reports.

Cruz’ former classmates say he had a hot temper and a history of making dark, gun-related jokes, according to USA Today.

Cruz is in custody. Of the seventeen fatalities, 12 happened inside the school, two just outside the school, one on street and two people died at the hospital.