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As throngs of patrons strolled and browsed at the Mall in Columbia on a gray, cold Saturday, shotgun blasts rang out and bodies fell as a familiar tragedy — homicidal lunacy in a crowded public place — brought terror to a suburban Maryland shopping complex.

It happened just after 11 a.m., about 25 miles northeast of Washington. A gunman opened fire on the mall’s second level, killing two employees of Zumiez, a clothing store for skateboarders and snowboarders, Howard County police said. Minutes later, when officers arrived, they found the shooter dead of an apparently self-inflicted wound.

Police said his body was laden with ammunition and a shotgun was on the floor. In addition, they said, his bag, which was found in the store, contained what they described as two crude devices that seemed to be an attempt to use fireworks to make explosives.

Although the violence ended quickly, the fear it caused among hundreds of shoppers lasted through the early afternoon, as workers and patrons rushed toward exits or huddled in hiding. Heavily armed officers dressed for combat scoured the mall, worried that the attacker might have had an accomplice. It turned out that he didn’t, police said.

Violence erupted at a suburban mall in Columbia, Md. on Saturday morning, after a shooter emerged from among weekend shoppers. Police confirmed that three people were left dead, including one believed to be the shooter.

Lauryn Stapleton, who works in the mall, was at a McDonald’s on the first level getting food for her boss when she heard loud noises and saw three people drop to the floor near an escalator.

“I was standing there when it happened,” said Stapleton, 18, shivering in the mall’s parking lot awhile later. “I didn’t know what to do.” What immediately came to mind, she said, was this: “I’m going to die!”

Police identified the slain employees as Brianna Benlolo, 21, of College Park and Tyler Johnson, 25, who had lived in Ellicott City but recently moved to Mount Airy.

As darkness fell Saturday, with the shopping complex still a sprawling crime scene, police continued trying to determine the motive for the shooting. “There are still a lot of details we need to confirm,” Police Chief William J. McMahon said.

McMahon said police did not fire any weapons during the incident, as officers found the shooter dead when they arrived. Although he had a large quantity of ammunition and had apparently tried to make explosives, it appeared that he did not target anyone else at the mall.

Police said they disabled the possible explosive devices, and, following standard procedure, would search the mall with K-9 units through the night.

A law enforcement official said Saturday night that police had identified the assailant and were working to obtain a warrant to search his Maryland home. Speaking on the condition of anonymity because the investigation is ongoing, the official said the killer used a 12-gauge pump-action Mossberg shotgun.

The three bodies were found “in and outside” Zumiez, McMahon said. The police chief said five other people in the mall needed medical treatment, one for a shotgun wound that was described as non-life-threatening, the others for minor injuries suffered in the frantic mass exodus from the shopping complex.

Police said a victim who was shot in the foot told them that she was on the lower level of the mall, below Zumiez, when she was injured. Detectives were investigating how the wound occurred.

Records show that the shooter bought the gun in Maryland within the past few months, according to a law enforcement official, who added that the victims appeared to have been hit by buckshot.

George Sliker, Johnson’s uncle, said he and other relatives frantically tried to contact Johnson after they heard about the shooting. Failing to reach him, Sliker said, they began calling hospitals. Then they drove to the mall.

“The odds kept narrowing,” said Sliker, 67, of Upper Marlboro. “They couldn’t get anybody to tell them anything. It was horrible for them.” He described his slain nephew as polite and upbeat — “a likable kid” — and said he could not fathom why anyone would want to shoot him.

“It’s very hard on the family, of course,” Sliker said. “He just seemed like an ordinary kid who was at the wrong place at the wrong time.”

Bryan Fischer, 34, said Johnson was a “kind of shy guy” who for the past several years had volunteered in an anti-drug program in Howard County schools. Johnson loved concerts and music, especially rave, dubstep and electronic dance.

“He was a very sensitive kid with a huge heart who was there to help anybody in need, always there with a smile or a joke, loving and caring, and one of the best friends anybody could ask for,” Fischer said.

Fischer said that Johnson did not socialize much with his slain co-worker, Benlolo, with whom he had worked at Zumiez since late last year.

Benlolo was an assistant manager at the store, according to Corey Lewis, who for the past two months was her housemate at a white duplex in College Park, just on the edge of the University of Maryland campus. Benlolo had a 2-year-old son who spent time with her at the duplex a few days a week, Lewis said, and posted numerous pictures of him on Instagram and Facebook.

“She was always kind and joyful,” Lewis said, noting that she had a smile on her face as she prepared to leave for work Saturday morning. “She never seemed like she had any negativity. This comes as a shock to everyone.”

Zumiez chief executive Rick Brooks said in a statement that the company is “deeply saddened by the violence” at the store. “The Zumiez team is a tight knit community and all of our hearts go out to Brianna and Tyler’s families,” he said.

Maryland Gov. Martin O’Malley (D) lamented the deaths in a statement, expressing his “deepest condolences to the families of the victims and all those affected by this senseless act of violence. Protecting the public’s safety is our most solemn obligation.”

At the suburban mall, a quiet Saturday turned to terror as the blasts jolted shoppers and employees, who hit the floor and scrambled into stores.

“It was pretty freaky,” said Robert Ashton, a 49-year-old Californian on a business trip to Maryland. He said he and two companions were in the first-floor food court, directly beneath Zumiez, when the shooting occurred. “You see these things on TV all the time,” he said. “But you never think you’re going to be in the middle of it.”

Ashton said he heard a boom from above that sounded like a table falling over. And then came more booms, at least three, he said. “We took off running” and found shelter at a Chick-fil-A with other mall patrons, including a woman with two toddlers and another with three children. They hid for about 45 minutes until police arrived.

Roger Aseneta, a manager at Auntie Anne’s pretzel shop, said he heard what he knew were gunshots about 11:15 a.m. He ushered his employees inside and locked the doors behind them. They went into a back room where, on a surveillance camera, they could see people running in the food court outside.

“It’s a case of people running for safety,” he said. “It’s a really terrible thing. I never thought I would experience this. . . . I was shaking.”

Aseneta, 52, said he heard five or six shots. And “I heard screaming,” he said in the parking lot, still in a white Auntie Anne’s apron.

At 12:30 p.m., police led frightened shoppers and workers from the mall entrance at the food court. Many were coatless, and those without cars were ushered, many shivering and some holding babies, into warm vans from Howard and Anne Arundel county fire departments. Some held hands and were crying.

Police officers guarded each entrance off Little Patuxent Parkway to keep people from the nearly empty parking lots. Police said the mall will be closed Sunday.

Laura McKindles said she heard eight to 10 shots as she worked a booth on the second level overlooking the food court.

“People were yelling, ‘Someone’s got a gun!’ ” she said. “They were screaming.”

She said she ran across the corridor and into a perfume store, where she hid in a back room for about 90 minutes until police gave the all clear. She was with three other workers from her stall and from the store. “I was praying,” she said. “I was thinking about my family, my dog.” She had left her cellphone behind and couldn’t call anyone to tell them she was okay until after she got out.

“I think this country is in a lot of trouble,” said McKindles, who recently moved to Columbia from north of Baltimore. “I mean, what possesses someone to, on a Saturday afternoon, in this cold, to come to a mall and shoot people?

“Why? I just can’t understand what motivates that.”

Lori Aratani, Lynh Bui, Alice Crites, Jennifer Jenkins, Jenna Johnson, Victoria St. Martin, Carol Morello, Martin Weil, Clarence Williams and Matt Zapotosky contributed to this report.