A journal discovered at Darion Marcus Aguilar's home may explain why the 19-year-old walked into a busy mall in Columbia, Maryland, on Saturday and killed two employees of a skateboard apparel shop before turning the shotgun on himself.
So far, law enforcement officials haven't determined a motive and aren't giving many details about the journal's contents. That's something people certainly will be talking about when the mall reopens for business at 1 p.m. ET Monday.
Police said Aguilar showed up at The Mall in Columbia in a taxi Saturday morning and stayed in a "generally confined area" before going to Zumiez, a shop that caters to skaters, on the second floor. There he fired six to nine shots, killing 21-year-old Brianna Benlolo and 25-year-old Tyler Johnson before shooting himself.
Police are trying to find out more about Aguilar. CNN affiliate WBALreported he was a quiet, tall, skinny skateboard enthusiast who graduated last year from Blake High School in Silver Spring. He had no criminal record and purchased the shotgun legally, WBAL said.
Aguilar had a backpack that contained two homemade bombs, police said. Both were disabled.
Howard County Police Chief Bill McMahon told reporters Sunday that in the journal, Aguilar "does express some general unhappiness with his life, but I really don't have any other information about that now."
But the journal had enough disturbing information to worry a Prince George's County police officer who saw it Saturday afternoon - before he knew Aguilar was the mall shooter, CNN affiliate WJLA said.
According to WJLA, the officer went to Aguilar's home in College Park to speak with his mother after a missing person report was filed. The officer read parts of the journal and was concerned for Aguilar's safety, the affiliate said.
The investigator traced his phone and discovered it was pinging at the Mall in Columbia, which had become a crime scene by that time, WJLA said. When the Prince George's officer delivered the information to the mall, Howard County police were able to identify Aguilar.
Aguilar also had a backpack that contained two homemade bombs, police said. Both were disabled.
McMahon said there was no known relationship between Aguilar and Benlolo, WBAL reported.
"I know there's a lot of interest in the motive for this, and I have as much interest in that as anybody," McMahon said Sunday.
McMahon identified Aguilar as the shooter Sunday.
Aguilar purchased the 12-gauge Mossberg shotgun in December, the chief said.
He added that police served a search-and-seizure warrant at the shooter's house and retrieved documents, computers and other potential evidence, including the journal.
On Saturday, a federal official briefed on the shooting told CNN that preliminary information suggested the gunman aimed only at the two victims, perhaps indicating it was an isolated situation and not a wider shooting spree.
Benlolo was an assistant manager at the store and had worked there since November 2012, according to her Facebook page.
Evelyn McDonald, her close friend, called the shooting shocking and a "complete tragedy."
"She was just full of energy. She was so nice and just an amazing artist and just an amazing person inside and out," McDonald told CNN.
Benlolo was the mother of a small boy.
"She loved her son. She loved being a mother," McDonald said.
Johnson had worked at the store for about three months, according to his Facebook page.
See more at CNN.com