Maryland mall shooter expressed 'general unhappiness' COLLEGE PARK, Md. - A day after another shooting brought community grief and national headlines, police said they had no explanation for why a 19-year-old skateboarder killed two skate shop employees and sent mall-goers running for cover before killing himself. Howard County Police Chief William McMahon told reporters Sunday that authorities had found a journal at the home where Darion Marcus Aguilar lived with his mother in College Park. In it, Aguilar expressed some "general unhappiness," McMahon said. Aguilar's mother reported him missing Saturday and showed an officer her son's journal, Prince George's County police said. The officer tracked Aguilar's phone to the Mall in Columbia, where the shooting had already played out. Aguilar took a taxi to the mall Saturday morning, armed with a 12-gauge shotgun and a backpack containing crude explosives made of flash powder and household items, McMahon said Sunday. Aguilar shot to death two employees of the Zumiez skate shop, Brianna Benlolo, 21, of College Park and Tyler Johnson, 25, of Mount Airy, police said. Five others were injured: One person was shot in the foot and four were hurt as they fled. Police said Aguilar had no apparent link with the victims. A former classmate said he may have bought his skate clothes at the store. Although Aguilar's home was within half a mile of Benlolo's, police said there was no indication he knew her or Johnson. Investigators were left to reconcile the suicidal killer with the gentle, affable student friends and family remembered. Aguilar's mother and his former classmates said he was a competent skateboarder, a vegetarian and a nice guy who didn't seem to have any particular interest in guns. "He's just a very good person," said a former classmate, Tydryn Scott, 18, who said she was Aguilar's lab partner for four years at James Hubert Blake High School in Silver Spring. Quiet, timid, but never shy. You know the kids in high school that are mad every day," and he wasn't one of them. Other former classmates agreed, with one tweeting: "Darion wasn't the local psycho. Chill with all that. Kevin Ayala, who skated with Aguilar, described him as "the type of guy that was friendly, but out of school he kept to himself. ... Honestly, I can't say I ever saw him upset or with any type of mood swings. Like I said, he was very quiet and calm. Ayala said he was "pretty sure" Aguilar bought his clothes at Zumiez, "because it's one of the closest skate shops around." Aguilar graduated from high school in May. He had been accepted at Montgomery College, a community college in the suburbs of Washington, college spokesman Marcus Rosano said in an email, but had never registered for classes or attended. Aguilar had no criminal record in Maryland. Police said he bought the shotgun legally a month before the shooting. The white, two-story house where Aguilar and his mother lived appeared well kept, with a Christmas wreath on the front door. No one answered the door, which was stuffed with reporters' notes and business cards. A neighbor, David Keer, said he didn't know Aguilar or his mother. It's one of the houses in the neighborhood that seems to have new people living in it every few years. It's a rental. A woman who identified herself as Aguilar's mother told a WNEW radio reporter, "He never had a gun before, never been interested in guns, never been interested in anything like that." She refused to give her name but added: "If you were to go into his room, you would see what a gentle, sweet kid he was. ... I don't know what happened; I really don't. It's so unusual; you can talk to any of his friends to find out what a gentle person he was. Johnson's Facebook page indicated he had worked at Zumiez since November. "We have lost a kind, positive son who reached out to help others in need, and he made a difference," his family said in a statement. Our prayers are with him and the other victims and all the people who have been touched by this violence. Benlolo, according to her Facebook page, was an assistant manager and grew up in Florida and Colorado before moving to Maryland in 2010. Photos of her 2-year-old son adorn her page. A family friend, Evelyn McDonald, told CNN that Benlolo "loved being a mother." Simon reported from Maryland and Pearce from Los Angeles. The Baltimore Sun contributed to this report.