ECKER LEFT BOGART and Lafferty in the little reading room and walked across the hall to the cafeteria. This was where it all started, and it seemed that the old checkerboard linoleum-floored space kept calling out to him.

Maybe like a Siren serenades a sailor to his doom.

He walked around the perimeter of the space, looked in the freezer, turned the corner, and checked the kitchen area, then the outdoor loading dock, which led off into the woods. Initially they thought the shooter had escaped that way. Well, many of them still thought that, which was why a forensics team had been scouring the entire path and its environs ever since Decker had discovered what he had in the cafeteria.

But Decker no longer believed it.

He came back in and parked himself in one of the chairs the kids used. His wide butt hung off both sides of it and he could almost hear the scream of the seat’s spindly legs as it supported a bulk not usually seen in a high school.

So why had the shooter really been in the cafeteria? It was far from where the shooting spree started. The farthest possible spot except for the office and the library, places that would have had people in them at that time of the morning.

7:28—Melissa Dalton heard the whooshing sound as the freezer door opened.

8:41—Cammie Man was caught on video.

8:42—Debbie Watson lost her face and her life.

Basically one hour and thirteen minutes were unaccounted for. What took all that time? If he was already dressed and gunned up? Why had he waited? Or had he waited at all? Perhaps he was doing something. Perhaps he was doing something critical to his plan that took some time.

Decker sat there for a few minutes while his mind chewed on this.

No one had been seen walking from the cafeteria to the far hallway where Debbie Watson had died. They had identified and interviewed two people—both teachers—who most likely would have seen someone walk that route at that time. It was not guaranteed, because a minute off here or there or a head turning to the right instead of the left and there would have been a blind spot.

But if the killer started in the cafeteria, he had to get to the other end of the school unseen. That was point A.

He had done it. That was point B.

Point C would be how he had done it. Point C was what Decker desperately needed to understand.

And then something trickled into the back of his head, was run through the meticulous filter that his mind had become because of a hellacious hit by a Bayou boy, and the trickle came out the other end reformulated into something.

Decker rose and hurried outside. He hustled over to the cornerstone of the school and read off the date.

1946.

He already knew this, but looking at the numbers seemed to bolster his confidence in the theory forming in his head. Colors had flashed in his mind when his gaze fell on some of the numbers, but colors did not interest him right now.

1946.

A year after the big war ended.

And a new one had almost immediately begun.

The Cold War.

Nuclear war threats. Armageddon. Kids huddling under their flimsy desks as part of emergency drills in case a hydrogen bomb was coming their way. As though an inch-thick laminate shield would protect them from the equivalent of a million tons of TNT.

Decker hustled back to the cafeteria, passing several suspicious-looking Bureau agents in the hall as he did so. He didn’t acknowledge them. He barely noticed them. He was on the scent. He had formed walls in his head that had compartmentalized everything down to this one line of inquiry that might answer the one question that seemed unanswerable.

He stood in the middle of the room and looked in all four corners, then pulled his gaze back. He went into the kitchen and did the same thing. Then the loading platform.

He didn’t see anything remotely close to what he was looking for. The problem was, he didn’t know enough. That was always the damn problem with police work.

I don’t know enough. The man who can’t forget anything doesn’t know enough. How ironic is that?

But if Decker didn’t know enough, then maybe the shooter didn’t either. Maybe the shooter had had to turn to someone who did know enough.

Or who knew someone who knew enough.

Now, that theory, if played out, might answer several questions.

The school was a facility, a building. Changes could be made. Changes undoubtedly were made here over the decades. The drop ceiling over his head had assuredly not been here in 1946. What else had been added or taken away?

Or covered up? Because it was no longer necessary? And then forgotten?

Decker slipped into the library and motioned for Lancaster to join him. She finished up a phone call and then hurried over to the entrance to the library where Decker was standing. Decker was acutely aware that Special Agent Bogart and his special agent note taker Lafferty were both watching him from a distant corner of the space.

He spoke to Lancaster in a low voice, his features relaxed. He might just be shooting the breeze with her. They turned and left together.

Once outside in the hall, Lancaster said, “Do you really think it’s possible? I mean, I never heard of such a thing.”

“Just because you haven’t heard of it, doesn’t mean it doesn’t exist.”

“You went here. Did you ever hear talk of something like that?”

“No. But then again I never thought to ask, either. And it might’ve been from a long time ago. In fact, it probably was.”

“But who would know for sure? From what you said, it could have been put in over sixty years ago. And maybe never used. Anybody who might have known about it is probably dead or nearly so.”

“How about students from back then?”

“Well, they’d be pretty elderly too. And the teachers are almost certainly all dead.”

“There has to be a way, Mary. Records have to be kept—”

They had walked outside, and Decker broke off his sentence as he looked to his left, where the old military base was.

“The Army might have record of it,” he noted.

“The Army! Why them?”

“That base has been here since, what, the thirties?”

“That’s right. My grandfather worked there along with half the other people in Burlington. They had a big buildup during World War II, like every other military installation in the country.”

“So clearly it was there before the school was built. And lots of parents who worked at the base sent their kids to Mansfield.”

Lancaster appeared to understand where he was going with this. “So you think they might have initiated it?”

“And what if Debbie Watson’s great-grandfather, who worked at the base starting in the late sixties, knew all about it, and told little Debbie when he went to live with them?”

“And you think she might have told the shooter?”

“I can’t think of another reason why he would have needed her.”

“But how would he have found out that Debbie would know something like that?”

“It could have been any number of ways. That’s not important. But if I’m right, we’ll know how the shooter got from the cafeteria to the back hall unseen. And if we can nail that down we might be able to work backward to where the son of a bitch came from.”

They hurried off to Lancaster’s car.

At the window watching them was Special Agent Bogart. And the man from Washington did not look pleased.

Next to him Special Agent Lafferty was busily writing down notes.