Reuben looked over Stone’s shoulders. “And you can’t really tell if they’ve been discharged or not.”

Stone moved to the HVAC ductwork and pulled out the drawing Milton had done. He glanced at a section of ductwork that rose straight to the ceiling.

“Why are you so interested in the HVAC, Oliver?” Reuben asked.

“If some sort of gas was used to kill Jonathan, then the killer would have to know that he’d be at an exact spot before knowing when to turn on the gas line from down here.”

Caleb said, “That’s right, I hadn’t thought about that. Since there was no fire to trigger the gas, it had to have been turned on manually. But to do that, you’d have to be in this room. So how could the killer know that Jonathan would even be in that part of the vault?”

“I think he knew Jonathan’s daily pattern. He was always the first one in the vault, and he regularly visited certain areas while he was inside, including the place where he died.”

Reuben shook his head. “Okay, but from what Caleb told us he found DeHaven’s body about twenty feet from one of the nozzles, meaning he was in the perfect place to be killed by the gas. But how would the person have known that all the way down here?”

Stone looked at Milton’s drawing and then pointed to the HVAC. “This trunk line feeds directly into the book vault, running through all levels of it.”

“So?”

Stone was looking around the HVAC and then stopped. On the side not visible from the main area, Stone pointed at something. Reuben and Caleb looked at the spot.

“Why would you have an access panel cut into the ductwork?” Reuben wanted to know.

Stone opened the small panel and looked inside. “Caleb, remember the vent in the ductwork near where Jonathan’s body was found. The grille was bent?”

“Yes, I remember you pointing that out. What about it?”

“If someone placed a camera attached to a long cable inside the ductwork in the book vault and bent the grille open, the camera would have a clean shot of the vault area where Jonathan was that morning. And if someone was down here with a receiver attached by that cable to the camera, I believe he could see everything going on up there, including Jonathan’s movements.”

“Damn,” Reuben said. “And they used the ductwork —”

“Because that was the only way to run the cable. A wireless signal might not go through all the concrete and other obstructions,” Stone said. “I think if we examine the ductwork inside the vault behind that bent grille, we’ll note some evidence of how the camera was hung. The person waits down here, sees Jonathan on the camera and hits the manual switch, having disconnected the warning horn beforehand, and in ten seconds the gas is fully dispersed and Jonathan dies.”

“But whoever did it would certainly have gone to retrieve the camera, so why didn’t he bend the grille back then?” Reuben asked.

“He might have tried, but once you start bending those grilles, it’s hard to get them back perfectly.” He looked at Caleb. “Are you all right?”

Caleb was ashen–faced. “If what you’re saying is true, then someone working at the library killed Jonathan. No one else could’ve entered the book vault unaccompanied.”

“What the hell’s that?” Reuben hissed.

Alarmed, Stone looked at the door. “Someone’s coming. Quick, behind here.”

They scrambled behind the HVAC system, Reuben having to half carry the terrified Caleb. They had barely gotten out of sight before the double doors opened. Four men came in, all wearing blue jumpsuits. Right behind them a forklift sailed into the room, driven by a fifth man. Another, obviously the boss, held a clipboard as the others gathered around him.

“Okay, we’re taking this one, this one and that one,” he said, pointing at three cylinders, including two attached to the piping. “And replacing them with the three on the forklift,” he added.

The men went to work carefully unhooking the enormous pressurized cylinders from the pipes while Stone and the others watched from their hiding place.

Reuben glanced at Stone, who shook his head and put a finger to his lips. Caleb was shaking so badly that Stone grabbed one of his arms and Reuben the other to try and steady him.

A half hour later the three cylinders were lifted up by the forklift and strapped on. Next the three cylinders the men had brought in were attached to the piping system. Then the forklift moved out of the room, with the other men trailing. As soon as the doors closed behind the men, Stone went over to the newly installed cylinders and read the labels. “FM–200. Caleb, you said the library was scrapping the halon system. They must be replacing it with this type of fire suppressant.”

“I suppose,” Caleb replied.

“Okay, we’ve got to follow them,” Stone said.

Caleb whimpered, “Please, Oliver, no.”

“Caleb, we have to.”

“I … don’t … want to die!”

Stone shook him hard. “Get ahold of yourself, Caleb. Right now!”

Caleb looked at Stone in stunned amazement and then sputtered, “I don’t appreciate you assaulting me.”

Stone ignored this. “Which way is the loading dock?”

Caleb told him, and as they were heading out, Stone’s cell phone buzzed. It was Milton. Stone told him what had happened. “We’re going to follow the cylinders,” he said. “We’ll keep you posted.”

• • •

Milton clicked off the phone and looked up at Annabelle. They were in her hotel room. He relayed what Stone had told him.

“That could be dangerous,” she said. “They don’t really know what they’re getting into.”

“But what can we do?”

“We’re their backup, remember?”

She ran to the closet, pulled out a bag and slipped a small box out of it.

Milton immediately looked embarrassed because it was a tampon box.

She noted his discomfort. “Don’t get all shy on me, Milton. Women always hide things they don’t want found in their tampon box.” She opened the box, took something out and slipped it in her pocket. “They said the name of the company was Fire Control. I’m assuming they’re going to the company’s storage facility. Can you find it?”

“Your hotel has WiFi, so I can look it up on the Net,” Milton said, his fingers already flying over the keyboard.

“Good. Is there a novelty store around here somewhere?” she added.

He thought for a moment. “Yeah. It’s got like magic stuff too. And it’s open late.”

“Perfect.”

Chapter 37

The Nova followed the Fire Control, Inc., truck at a discreet distance. Caleb was driving, Stone next to him and Reuben in the rear.

“Why don’t we just call the police and let them handle it?” Caleb complained.

“And tell them what?” Stone said. “You said the library is having the old system scrapped. For all we know, that’s all those men are doing. And it might alert the wrong people that we’re on to something. We need stealth here, not the cops.”

Caleb snapped, “Terrific! So I have to go in harm’s way instead of the police? What the hell I pay taxes for I’m sure I don’t know.”

The truck turned left and then hung a right. They had passed through the Capitol Hill area and entered a run–down part of town.

“Slow down,” Stone said. “The truck’s stopping.”

Caleb eased the car to the curb. The truck had halted at a chain–link gate that another man inside the complex was now opening.

“It’s the storage facility,” Stone said.

The truck pulled through, and the gate was locked behind it.

“Well, that’s all we can do here,” Caleb said in a relieved tone. “My God, do I need a decaf cappuccino after this nightmare of an evening.”

Stone said, “We need to get inside the fence.”

“Right,” Reuben agreed.

“Are you both insane!” Caleb cried out.

“You can wait in the car, Caleb,” Stone said. “But I have to check out what’s going on in there.”

“But if you get caught?”