Darion Aguilar showed signs of mental illness that went untreated, according to police.
Howard County Police say the teenager behind the deadly shooting at the Columbia Mall on Jan. 25 acted alone and was aware that he suffered from a mental disorder, but never sought any professional help and hid his condition from his parents.
Howard County Police Chief Bill McMahon dismissed speculation that 19-year-old Darion Aguilar specifically targeted the two victims of the attack — 21 year-old Brianna Benlolo and 25 year-old Tyler Johnson — saying Aguilar did not know the two employees of Zumiez's skateboard shop.
Police came to the conclusion that this was a random attack after conducting hundreds of interviews and extensively reviewing Aguilar's computer, phone and other records. That provided a glimpse into the mind of a troubled young man.
"We find out that he was looking at some very disturbing and violent images," McMahon said. "He's visiting sites that are devoted to mass shootings, including those at schools and at malls."
Police believe Aguilar was fixated on the 1999 Columbine High School massacre.
"He shows a particular fascination with the Columbine shooting," McMahon said.
In fact, investigators believe that fascination led Aguilar to delay the start of his shooting spree for 40 minutes so he could begin at 11:14 a.m., the time the Columbine massacre began. Police say the College Park resident hid in Zumiez's dressing room after assembling the shotgun he had carried inside a backpack full of ammunition and home-made explosives and then changed into clothing similar to that worn by the Columbine killers.
Investigators found a self-picture on the Tumblr site which Aguilar apparently took minutes before he began his suicidal rampage. He also wrote "Today is the day...I feel no sympathy or empathy... I could care less."
McMahon says the investigation pieced together the final year of Aguilar's life and through his web searches detectives realized the young man was struggling with suicidal thoughts and mental illness but never acknowledged this to his parents or sought psychiatric help.
Police used video from an ATM, street and mall cameras to reconstruct the final six hours of his life. They have detailed images from the time he left his home at 5:15 a.m., got in a taxi, withdrew money from an ATM, entered the mall and began his shooting rampage until the time he died by putting a shotgun in his mouth and pulling the trigger.