“But the shooter still couldn’t be tearing into walls, floors, or ceilings, because that would also make noise and leave evidence behind of how he went from here to the back hall.”

“Well, he did leave evidence he was in here. The spoiled food, remember?”

“He did that on purpose. He could have easily turned the temp back down once he came out of it. Hell, he didn’t have to stay in the freezer all night anyway. He wanted us to know he was here. But he didn’t want us to find how he got from the front to the back. At least not right away. That’s the reason he left the trace in the ceiling and the tile dust on the floor. Classic misdirection. He’s screwing with us. And he’s costing us time. All good for him and bad for us.”

Lancaster kept glancing around. “So we’re looking for an entrance in here that’s been sealed up. We just don’t know how or where.”

“The term ‘sealed’ can mean a lot of different things. But the point is, our guy befriended Debbie for one reason and one reason only—to learn about this passage.”

“Come on, Decker. How would he even know about it to ask her?”

“I found out about it based on observations and hunches and a little research. He could have done the same. This is a relatively small town. He could have found out Simon Watson worked at the base any number of ways. He could have learned he once lived with the Watsons. He could have approached Debbie to see if she knew anything about it. And of course she did.”

“That takes a lot of planning and forethought.”

“And that apparently is a strong suit for our guy.”

Decker walked back and forth in front of a section of the wall.

Lancaster noted this and said, “I bet those rules haven’t changed in sixty years. I suppose you adhered to all of them when you went here?” she added with a smile tacked on.

The “rules” she was referring to were posted on a large section of the wall that Decker was studying. They included no loud talking, no throwing food, no eating off someone else’s plate, no milk cartons left on tables, all trash in the garbage, no running, and on and on.

“Amos, I said—”

He held up his hand for her to stay quiet, while he paced the wall and then looked at the floor.

“What do you see down there, Mary?”

She bent low and looked where he was pointing.

“Some marks. Probably from a student’s shoes.”

“I don’t think so. There’s no uniform requirement at Mansfield. Most boys wear sneakers. And from what I’ve seen, most girls wear sneakers, flats, or chunky heels. That footwear wouldn’t leave those sorts of marks. It’s actually scraped into the linoleum. And they’re not short, like a heel might make. They’re long. And they’re on a slight curve. Looks to be a few of them.”

“Well, what do you think they are?”

He stood closer to the section of wall where the rules were printed on a massive piece of wood painted to match the wall color. The wood ran down to the floor and nearly to the ceiling.

“No hinges evident,” he said. “But—”

He dug his fingers under the right section of the wall and tugged at various spots. He did this on the other side. Finally, after ten minutes of probing, tugging, and pushing, there was a little click and the entire section behind the sign opened outward. He pulled on it, opening it farther. Revealed behind it was a pair of old wooden doors painted the color of the wall.

“Look at the floor,” said Decker.

Lancaster noted another set of fresh scuff marks where the wood had dragged in one place across the floor when he’d opened the section.

“Damn, Amos. The mark on the floor was from the door swinging open.”

“Hinges were placed about a foot in and mounted on a support structure so they wouldn’t be visible to anyone. But the hinges have sagged a bit over time, hence the scuffed floor.” He ran his finger along one set of hinges and his finger came away darkened.

“Recently oiled,” he said.

There was a small knob in the center of the back of the section.

“What do you think that was for?”

Decker thought for a few moments. “You’d use it to pull shut the wall section once you’re on that side of it.”

“Right. But why even have a door at all? If they wanted to seal it up, why not just seal it up?”

“I don’t know, Mary. It must have cost a lot of money to build. Maybe they wanted to have reasonably easy access to it if they ever decided to use it again.”

“I guess.”

“Could be,” said Decker.

Decker pointed to the floor once more. In the dust were clear sets of shoeprints heading in the direction they were going.

Two clear sets of footprints heading down the passage.

“Walk to the right, Mary, so we preserve them. And take shots of them with your phone camera as we go.”

“Okay, but why two sets? Are they two different people?”