Darion Aguilar, the 19-year-old gunman who opened fire in a Maryland shopping mall Saturday, killing two people and himself, was a “mall rat” who occasionally hung out in the skateboarder shop where the shootings occurred, a store employee said Tuesday.

Quy Vo, 19, said he had been scheduled to work Saturday at Zumiez, which sells apparel for skaters and snowboarders. But about 11:15 a.m. — 45 minutes before Vo’s shift was to begin — Aguilar entered the store, at the Mall in Columbia, and fatally shot two employees. He then turned his 12-gauge shotgun on himself, Howard County police said.

Police said Tuesday on Twitter that Aguilar “frequented [the mall], would hang outside and smoke in small groups. Unknown if he’d been in Zumiez before.”

Five people suffered minor injuries in the frenzy after the shootings as hundreds of frightened shoppers scrambled for cover or rushed to get out of the mall.

Although Vo recalled Aguilar as a browser at Zumiez, he said he could shed no light on the motive for the violence. Investigators said they also remain stumped. Police said they are continuing to analyze Aguilar’s financial records, a computer taken from his College Park home and a cellphone found on his body. “So far no new info discovered,” police said in a tweet.

Darion Marcus Aguilar (AP)

Vo said that Aguilar would “come to hang out and visit the store,” that he would “skate around the mall [on his skateboard] and come to Zumiez.” Vo said he learned of Saturday’s attack while he was at home in Silver Spring, getting ready for work.

Vo, also a skateboarder, said the area around the mall and a nearby lake are favorite skater hangouts. He said he wasn’t surprised that Aguilar would travel to Columbia from College Park, about 20 miles away. “It’s just a popular area,” said Vo, who added that he also saw Aguilar occasionally at a skateboarding park in Laurel.

Vo said he doesn’t recall any odd behavior by Aguilar or unusual encounters involving Aguilar and the victims, Brianna Benlolo, 21, and Tyler Johnson, 25. “Just customer greetings, that’s it, nothing more,” Vo said. He also said he doesn’t recall Aguilar buying anything.

Benlolo lived in College Park, not far from the house Aguilar shared with his mother. Johnson lived in Mount Airy. Police said they had found no evidence that Aguilar knew the victims or had any prior connections to them.

Police said they are continuing to study a journal that Aguilar kept in which he expressed hatred for certain groups and unhappiness with his life. “Shooter’s handwritten journal offers no insight into whether he knew the victims,” police said in a tweet. In another tweet, they said Aguilar “knew he was having mental health issues.”

Also on Tuesday, a spokesman for the Maryland medical examiner’s office said Aguilar shot himself in the face after killing the two Zumiez employees.

An autopsy found that Aguilar died of an “intraoral shotgun wound” — meaning that he pulled the trigger with the barrel in his mouth — and that the manner of death was suicide, according to Bruce Goldfarb, a spokesman for the chief medical examiner. The autopsy results were first reported by the Baltimore Sun.

The medical examiner determined that Benlolo and Johnson also died of shotgun wounds, Goldfarb said. He said that Benlolo was wounded in the neck and the chest and that Johnson suffered multiple wounds. He declined to say where Johnson was shot.

A full autopsy report, which would include toxicological information, is expected to take 60 to 90 days, Goldfarb said. Those tests would reveal whether Aguilar used any medications or intoxicating substances before the shootings.

Vo described himself as a close friend of Benlolo’s. Both had started working at the store on the day after Thanksgiving in 2012. He said that when he learned of the shootings, he started calling every cellphone number he had for co-workers.

“Including Bri,” he said, referring to Benlolo. “She was the only one who didn’t pick up.”

He said he was devastated to learn that she had been killed. “She didn’t deserve to die,” he said. “She worked hard to get where she’s at. She’s a very energetic person.”

As for Aguilar’s motive, Vo said: “I’ve asked myself that a million times. I think he was a sad person and just took it out on somebody he didn’t need to.

“I guess he didn’t want to die alone.”

Paul Duggan and Peter Hermann contributed to this report.

Get updates on your area delivered via e-mail.