Police say they know who shot two people, and then himself, inside a crowded suburban mall not far from Washington, D.C. Saturday.
But they still don't know why.
Sunday, police identified Darion Marcus Aguilar, of College Park, Md., as the gunman who shot and killed two people at the Mall in Columbia in Columbia, Md. Saturday. Aguilar died of an apparently self-inflicted gunshot wound, police said.
One other person was shot and injured, and four more people were injured as shoppers rushed to find shelter in the chaos after the shooting.
Late Sunday, police said they had not determined a motive, or even how Aguilar and the two victims were related.
"At this point -- we still have more work to do, still have more interviews to do -- we have no known relationship between the victims and our shooter," Howard County Police Chief Bill McMahon said at a news conference late Sunday.
The police have seized evidence from Aguilar's home, including a journal in which he expressed "general unhappiness" about his life.
But a motive is still elusive. "There are a lot of unanswered questions,'' McMahon said at another news conference, earlier Sunday.
Aguilar's body was found near a Mossberg shotgun and ammunition, police said. They also said the shooter had a backpack with explosives in it.
The homemade devices included flash powder and household items, police said Sunday. McMahon called them "not very sophisticated."
Overnight, police searched the mall, including all its stores, with almost 20 bomb-detecting K9 teams. They did not find any other explosives.
Also overnight, police tracked Aguilar's progress through the mall on surveillance video. It shows Aguilar took a cab to the mall, getting there about 10:15 a.m., McMahon said. Aguilar went downstairs in the mall, then came back upstairs to the site of the shooting.
Police said Aguilar fired six to eight shots from the shotgun, apparently purchased in December in Montgomery County, Md.
Police said Saturday the two killed were Brianna Benlolo, 21, of College Park, Md. and Tyler Johnson, 25, originally of Ellicott City, Md. and more recently of Mt. Airy, Md. Both were employees of Zumiez, a store on the upper level of the mall that caters to teen shoppers.
McMahon said it took officers longer to identify Aguilar because they feared his body may have been booby-trapped with explosives. Police used robots to help check the body.
Police also have searched the Hollywood Road home in College Park where Aguilar lived with his mother, and seized some potential evidence.
So far, little is known about Aguila. Police said he had no criminal record.
He graduated in 2013 from James Hubert Blake High School in Montgomery County, said Dana Tofig, a schools spokesman. Students who attended school with Aguila said he was an avid skateboarder.
The five people who were injured were transported to Howard County General Hospital. The injured were treated and released Saturday, according to the hospital.
The mall was closed Sunday; it will reopen Monday at 1 p.m. There are two memorial sites planned Monday, one at the entrance near Starbucks, the other inside at center court.
The shooting threw the popular mall into chaos. Witnesses described hearing the shots shortly after 11 a.m., and watching some victims fall, while others fled.
"They just kept shooting and it didn't stop," said one witness.
She said she heard what sounded like "something being dropped" and then realized the sound was gunshots.
She rescued one child and then ran back to her job at a children's hair salon to secure the others.
"I work in Cartoon Cuts; I was downstairs getting a tea for my boss," she said. "And all of a sudden I heard ... it sounded like someone dropped something. And all of a sudden I see people fall, three people fall to the ground. I don't know what happened to them. And all I see is people going down to the floor and running.
"I just saw everybody run, so I ran."
Another shopper said he was in Sears when the shots rang out. "I heard a bang, and I was like man, that kinda sounds like a gunshot," said the young man.
"Then I see people running, and I hear some people screaming, and I heard it again -- boom, boom, boom. And people just started screaming and running. It was just complete madness."
Another eyewitness, a young woman, said she was in a PacSun store when the shooting happened: "We just heard gunshots, and then this lady came into the store and said there's a guy with a gun ... Me and my friend just ran in the back room.
"We were crying and we were just scared out of our minds, because our thought was that we were going to get shot."
News4 spoke to one man who said he was in phone contact with his daughter, who was taking shelter in a Bank of America inside the mall, along with dozens of others.
"People were panicking," the man said.
Zumiez issued a statement on its Facebook page Saturday evening expressing deep sadness over the shooting: "The Zumiez team is a tight knit community and all of our hearts go out to Brianna and Tyler’s families."
The mall, which is officially named "The Mall in Columbia" but is widely known as Columbia Mall, is located in Columbia, Md., between Washington, D.C. and Baltimore.
"The Columbia Mall has a very unique place in the county," McMahon said Sunday. "It's not just an economic institution. It's really a place of community."