Police promised a strong security presence when The Mall in Columbia outside Baltimore reopens Monday at 1 p.m.
The Zumiez store, scene of Saturday's shooting rampage that left the gunman and two others dead, will not be open or visible, Howard County police said in a statement.
"Come help reopen #ColumbiaMall today at 1pm. #HoCoPolice will be there, hope you will too. Together, we are stronger," the department said in a tweet.
Police Chief Bill McMahon said officers have interviewed friends and family members of gunman Darion Aguilar, 19, a quiet, skinny teen less than a year out of high school who had no previous problems with the law.
McMahon said police still cannot confirm a motive for the shooting, although in his journal Aguilar expressed "general unhappiness with his life."
Aguilar, who lived in College Park, Md., fatally shot two people who worked at Zumiez, an apparel store catering to skaters and snowboarders, before killing himself. McMahon said it was not clear whether Aguilar, of College Park, Md., knew either of the victims, Brianna Benlolo, 21, of College Park, and Tyler Johnson, 25, of Mount Airy.
Police said Aguilar used a Mossberg 12-gauge shotgun that he bought legally in December. They believe Aguilar died from a self-inflicted gunshot wound. The shotgun was found near his body.
Aguilar arrived at the mall by cab around 10:15 a.m. Saturday. Reports of shots came an hour later.
Aguilar carried a backpack containing homemade explosive devices. He also had a great deal of ammunition, McMahon said.
Another victim was shot in the foot. Police believe Aguilar fired between six and nine shots inside and outside the Zumiez store, which is on the mall's upper level.