He had arrived at the mall with a Mossberg 12-gauge shotgun, a large amount of ammunition and a bag in which they found two crude devices made of "flash powder and household items."
Aguilar, of College Park, had disrupted the Saturday morning bustle at the mall, a gathering place for many in the planned suburban community, scattering panicked shoppers and killing employees before shooting at others in the mall.
The devices were rendered harmless by law enforcement, McMahon said, and no other booby traps or explosives were found in the mall after 20 explosive canine teams searched the mall.
Police still did not release a possible motive of the gunman, who was found just outside the store on the mall's second floor above the food court. Police K-9 units were going to search the entire mall overnight, police said.
"We have not been able to verify any type of relationship between him and our victims," Howard County Police Chief Bill McMahon said, adding that police are still actively looking for connections and a motive. Aguilar lived near victim, Benlolo, but McMahon didn't know if they knew each other.
Surveillance video showed that Aguilar arrived at the mall at about 10:15 a.m. in a cab and walked into the upstairs entrance near the mall carousel. He then walked downstairs before he came back upstairs. Police report shots fired about an hour after he arrived.
On Sunday, the family of victim Tyler Johnson, issued a statement that said: "We have lost a kind, positive son who reached out to help others in need, and he made a difference. Our prayers are with him and the other victims and all the people who have been touched by this violence."
"We want to find out why this occurred," McMahon said. Police are planning to reinterview the victims' families to again search for connections between Aguilar and Benlolo and Johnson but he said investigators also want to respect their grieving process.
McMahon said police have seen nothing in Aguilar's background that hinted at violence. According to Maryland electronic court records, he did not have a criminal record.
No one answered the door at the well maintained, old white frame house in College Park where Aguilar lived, although there was a car in the driveway and lights on inside.
Neighbors said they did not know the family who is believed to be renting the house, except to see them coming and going occasionally. "I don't think they have been there long," said Augusta Bailey, a neighbor who has lived in her house for two decades.
Five people, including a woman who was shot in the foot on the first floor, were treated at Howard County General Hospital and released. The other four were not shot but injured during the chaos after the shots rang out.
A witness, Shafon Robinson, said the shooter appeared to be between 18 and 21 years old and was wearing khaki pants and a white shirt. Robinson said a young girl who was with her in the first-floor food court below Zumiez shrieked in fear, prompting the man to look down at them.
"He looked straight at me," Robinson said, and he reloaded the shotgun and aimed it at her. "He pointed the gun at me and looked at my eyes," she said.
Robinson's husband, Terrance Lilly, screamed at her to get down, which she did as a shot went over her head. It struck a wall behind her, spraying her clothes with dust, she said. Another shot hit the cover of a nearby fire extinguisher, Robinson said.
Meanwhile, Lilly ran upstairs to get their children, who were at the merry-go-round on the second floor near the shooting, Robinson said. He got them out of the mall, but in jumping over a table and railing broke bones in his face in three places, she said. He was taken to Howard County General Hospital and then to Maryland Shock Trauma Center for surgery.
Other shoppers and employees ran to escape the gunfire or to hide in storage closets or the back rooms of shops. The mall, a centerpiece of the new town created by Jim Rouse in the 1960s, turned into an unlikely crime scene: Heavily armed law enforcement officers, local, state and from the FBI and other U.S. agencies, descended on the mall. Overhead, medevac, media and police helicopters circled.
McMahon was among the local officials and civic leaders who expressed sympathy for the victims' loved ones during a late-afternoon news conference. "Our hearts go out to the families of the people who lost their life today," McMahon said. "This shouldn't happen in Columbia mall, it shouldn't happen anywhere, but unfortunately that's where we are as a society."
