Nick allowed Yarden to cue up the video for him. He had already tagged several segments from cameras on the third floor, particular instances that had drawn attention before the bombs went off.

“We were watching them,” the little man told Nick, as his long fingers flew around the computer keyboard, poking with incredible ease and efficiency. “Shoplifters often use backpacks. And they’ll work in teams. That’s what we thought was going on.”

Yarden sat back and let the first video play. He folded his arms over his chest, shooting glances at Nick, as if anxious for his reaction. Nick leaned forward. The film was grainy, black and white but the angle was decent. The backpacks looked ordinary. Not trendy. Big and bulky and, from the shift in this young man’s walk, heavy.

Yarden keyed up another video on a second monitor, but left the first playing.

The second young man was shaggy-headed, a bit shorter and thin. The backpack was identical.

At first glance it bothered Nick that these guys looked like older versions of his nephew, Timmy and his friend, Gibson. Clean-cut young men, ordinary with confident strides. There were no slumped shoulders. No shifty eyes or heads darting from side to side. They didn’t look at all like nerds or social misfits. Nothing like perhaps Klebold or Harris who had been responsible for the Columbine school shootings.

What was even more disturbing to Nick was that they didn’t look anything like he expected a suicide bomber to look. Did he expect brown-skinned Arabs? Yeah, he did. And he knew he wasn’t alone. Someone suggests suicide bomber and the mind readily conjures up that racial profile.

“They aren’t exactly what you’d expect, are they?” Yarden asked as if he could hear Nick’s thoughts.

“No. Not exactly.” He avoided glancing at Yarden, wanting to at least appear objective. He suspected the security officer was looking for Nick’s approval, hoping to bond, confidants taking sides in what could turn into a finger-pointing showdown. “Do you have any decent front facial shots?”

“All of us have been upstairs helping.” Yarden suddenly sounded offended. “I only had a few minutes with these before I left to pick you up.”

“Sure. I understand.”

“I thought that was supposed to be your job.”

“Yes, you’re absolutely right.” Nick could play the diplomat if needed.

“I found a flash. And one of the explosions.” Yarden started stabbing at the computer keys again, ready to please and make up for not having what was requested. He fast-for-warded a video clip, shoppers in full-speed animation. Then he stopped and freeze-framed, taking a few more seconds and zooming in before he started the video again.

Nick watched, amazed that even without sound the wall of bricks exploding in front of him made him wince.

“Where is this camera?”

“All of these are third floor. This one is around the corner from the food court.”

“Play it again,” Nick asked. “Only this time in slow-mode. And zoom out.”

“Zoom out?”

“Yes.” He didn’t even glance at Yarden to acknowledge his skepticism. Instead, Nick leaned forward and waited.

The shot took in the entire stretch of the long hallway, brick walls on both sides. One side had interruptions of doorways. The other was solid. Signs hung above the doorways and in several other locations. Nick watched the wall explode again. It was the side with the interruptions.

“What’s on the other side of that brick wall?”

“There’s not much down this hallway. Some offices. Restrooms.”

“Play it again,” he asked.

This time just before the wall exploded, Nick pointed at the monitor. “Stop.”

Yarden responded quickly.

“Zoom in on this sign.”

Yarden obeyed immediately, no hesitation. The sign read WOMEN.

“Is the men’s restroom next door?” Nick asked.

Yarden quickly consulted a map of the third floor that was spread out across a bulletin board.

“The men’s restroom is clear down at the end of this hall and,” Yarden said, his voice higher than normal, “on the opposite side.”

“So this explosion came from—”

“The women’s restroom.”