COLUMBIA, Md. -- The gunman who killed two people at a Maryland mall was a teenage skateboarding enthusiast who had no criminal record before he arrived there with a shotgun, plenty of ammunition and a backpack filled with crude homemade explosives, authorities said Sunday.
Darion Marcus Aguilar, 19, took a taxi to the Mall in Columbia in suburban Baltimore on Saturday morning and entered the building near Zumiez, a shop that sells skateboarding gear. He went downstairs to a food court directly below the store, then returned less than an hour later, dumped the backpack in a dressing room and started shooting, police said.
Shoppers fled in a panic or barricaded themselves behind closed doors. When police arrived, they found three people dead -- two store employees and Mr. Aguilar, who had killed himself, authorities said.
The shooting baffled investigators and acquaintances of Mr. Aguilar, a quiet teenager who graduated from high school less than a year ago and had no previous run-ins with law enforcement. Police spent Sunday trying to piece together his motive, but it remained elusive.
Mr. Aguilar, who had concealed the shotgun in a bag, fired six to nine times. One victim, Brianna Benlolo, a 21-year-old single mother, lived half a mile away from Mr. Aguilar in the same College Park neighborhood about 20 miles south of the mall, but police said they were still trying to determine what, if any, relationship they had.
Although they lived close to the University of Maryland, the state's largest college, neither was a student there. Mr. Aguilar was accepted last February to Montgomery College, a community college in the Washington, D.C., suburbs, but school spokesman Marcus Rosano said he never registered or attended.
The other employee, Tyler Johnson, did not know Mr. Aguilar and did not socialize with Ms. Benlolo outside of work, a relative said.
Tydryn Scott, 19, said she was Mr. Aguilar's lab partner in science class at James Hubert Black High School and said he hung out with other skaters. She said she was stung by the news.
"It was really hurtful, like, wow -- someone that I know, someone that I've been in the presence of more than short amounts of time. I've seen this guy in action before. Never upset, never sad, just quiet, just chill," Ms. Scott said. "If any other emotion, he was happy, laughing."
Mr. Aguilar graduated in 2013, school officials confirmed.
The Prince George's County Police Department said it received a missing persons report for Mr. Aguilar at about 1:40 p.m. Saturday, more than two hours after the mall shooting. Officers went to Mr. Aguilar's home to speak with his mother about 5 p.m. and saw Mr. Aguilar's journal. The portion the officer read made him concerned for Mr. Aguilar's safety, the department said.
Police began tracking Mr. Aguilar's phone and soon discovered it was at the mall.
Howard County Police Chief William McMahon said the journal expressed general unhappiness, but he did not give any specifics about the writings.
"There are a lot of unanswered questions," Chief McMahon said.
Mr. Aguilar purchased the 12-gauge shotgun legally last month at a store in neighboring Montgomery County.
At his home, officers also recovered more ammunition, computers and documents, police said.
The home is in a middle-income neighborhood called Hollywood, near the Capital Beltway. No one answered the door Sunday morning.
Five other people were hurt in the attack, but only one was hit by gunfire -- a woman who was hit in the foot upstairs near Zumeiz. All were released from hospitals hours later.
The mall was to reopen this afternoon.