Inside, McMahon said, he changed into a white T-shirt. At 11:14 a.m., he uploaded a photo of himself in the dressing room with his shotgun around his shoulder to his Tumblr social media account along with a message:

"I had to do this," he wrote. "Today is the day. On previous days, I tried this, I woke up with anxiety, regret and hope for a better future. This day, I didn't. I woke up, felt no emotions or empathy, no sympathy. I will have freedom or maybe not. I could care less."

Police believe the photo, no longer publicly visible, was an image he wanted to be remembered by. McMahon said his department does not plan on releasing the image. "We're not going to honor that intention," he said.

A minute later, Aguilar began shooting, killing Benlolo with one shot and firing upon Johnson multiple times.

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He fired two shots outside the store and wounded a 49-year-old Hanover woman in the heel before walking to an overhang and firing at the downstairs food court near the Great American Cookies store. He turned and fired again toward a Zumiez mannequin.

Aguilar then put the gun to his mouth and pulled the trigger, an act McMahon said mimicked a Columbine killer. The gray backpack full of explosives had been left in the dressing room, but did not detonate — police said it needed an electric charge or lit fuse to activate it. Had it gone off, McMahon said, it could have wounded someone nearby but would not have caused mass injuries.

Aguilar fired nine shots and stopped, McMahon said. The police chief speculated that by that time, victims had run or hidden, leaving no targets.

"Why did he stop shooting?" McMahon asked. "He had more ammunition. The only person who can answer that is the shooter."