Darion Marcus Aguilar liked cooking shows. He wanted to be a chef. He liked to spend summer afternoons at the Martin Luther King Jr. Swim Center in Silver Spring. Harmless. That’s what his friends say. Unremarkable.

He has no criminal record that police or online court records can turn up. He’s had no contact with Maryland’s mental health system that authorities have found, law enforcement officials said.

But on Saturday, Aguilar, 19, who graduated from James Hubert Blake High School in Silver Spring in June, shot and killed two people and himself at a skateboarding and surfing clothing store at the Mall in Columbia. Aguilar’s friends are trying to figure out what they missed or whether they should have seen the violence coming.

“He was a good person. He always believe[d] in inner peace, that is why it was so shocking to believe that he was the shooter,” said Peter Chu, a Blake classmate who is now a freshman at the University of Maryland Baltimore County.