A school official told the Associated Press on Tuesday that police found items necessary for making explosives at the home of Santa Monica shooter John Zawahri seven years ago.
Zawahri opened fire at Santa Monica College last week, killing five people, according to investigators.
Oscar de la Torre of the Santa Monica-Malibu Unified school board told AP Zawahri's behavior raised concerns seven years ago, when bomb-making materials were found in his home. Twenty-four-year-old Zawahri would then have been a minor.
"It was some type of devices or materials that would be able to make explosives, and the word 'pipe bombs' was what was referred to," de la Torre told AP. "If it was guns and stuff like that it would have been more serious, but because it was explosives, it wasn't deemed 'Oh my God,' just that this guy had a fascination."
Read more from GlobalPost: Santa Monica College gunman had mental health issues
At the time, Zawahri was attending Olympic High school, an institution that works with students with troubled pasts. The school did not kick him out after finding out about the bomb materials, but Zawahri never finished his studies, according to de la Torre.
The shooter is believed to have murdered his 25-year-old brother, Chris, and his 55-year-old father Samir Zawahri before setting the family's Southern California home on fire. He proceeded to Santa Monica College, where he went on a deadly ten-minute shooting spree, according to the Los Angeles Times.
Questions have been raised as to Zawahri's mental health, but investigations are ongoing.