I t was pitch black.

There was no moon, no stars, just low-lying rain-bloated clouds, as black as the sky. Dillon Savich was sweating in his Kevlar vest even though it was fifty degrees.

He dropped to his knees, raised his hand to stop the agents behind him, and carefully slid into position so he could see into the room.

The window was dirty, the tattered draperies a vomit-brown, with only one lamp in the corner throwing off sixty watts. The rest of the living room was dark, but he could clearly see the teacher, James Marple, tied to a chair, gagged, his head dropped forward. Was he asleep or unconscious? Or dead?

Savich couldn’t tell.

He didn’t see Marvin Phelps, the sixty-seven-year-old man who owned this run-down little 1950s tract house on the outskirts of the tiny town of Mount Pleasant, Virginia. From what they’d found out in the hour before they’d converged on this small house, Phelps was a retired math teacher and owned the old Buick sitting in the patched drive. Savich knew from his driver’s license that Phelps was tall, skinny, and had a head covered with thick white hair. And for some reason, he was killing other math teachers. Two, to date. No one knew why. There was no connection between the first two murdered teachers.

Savich wanted Phelps alive. He wanted the man to tell him why he’d caused all this misery and destroyed two families. For what? He needed to know, for the future. The behavioral science people hadn’t ever suggested that the killer could possibly be a math teacher himself.

Savich saw James Marple’s head jerk. At least he was alive. There was a zigzagging line of blood coming over the top of Mr. Marple’s bald head from a blow Phelps must have dealt him. The blood had dried just short of his mouth.

Where was Marvin Phelps?

They were here only because one of Agent Ruth Warnecki’s snitches had come through. Ruth, in the CAU-the Criminal Apprehension Unit-for only a year, had previously spent eight years with the Washington, D.C., police department. Not only had she brought her great street skills to the unit, she’d also brought her snitches. “A woman can never be too rich, too thin, or have too many snitches” was her motto.

The snitch had seen Marvin Phelps pull a gun on a guy in the parking lot of a small strip mall, pull him out of his Volvo station wagon, and shove him into an old Buick. The snitch had called Ruth as he was tailing them to this house, and told her he’d give her the whole enchilada for five hundred bucks, including the license plate number of the man taken. Savich didn’t want to think about what would have happened to Mr. Marple if the snitch hadn’t come through.

But Savich shook his head as he looked at the scene through the window. It didn’t fit. The other two math teachers had been shot in the forehead at close range, dying instantly. There’d been no kidnapping, no overnight stays tied to a chair with a sixty-watt bulb chasing the shadows. Why change the way he did things now? Why take such a risk by bringing the victim to his own home? No, something wasn’t right.

Savich suddenly saw a movement, a shadow that rippled over the far wall in the living room. He raised his hand and made a fist, signaling Dane Carver, Ruth Warnecki, and Sherlock that he wanted everyone to stay put and keep silent. They would hold the local Virginia law enforcement personnel in check, at least for a while. Everyone was in place, including five men from the Washington field office SWAT team who were ready to take this place apart if given the word. Every corner of the property was covered. The marksman, Cooper, was in his place, some twenty feet behind Savich, with a clear view into the shadowy living room.

Savich saw another ripple in the dim light. A dark figure rose up from behind a worn sofa. It was Marvin Phelps, the man whose photo he’d first seen just an hour ago. He was walking toward John Marple, no, swaggering was more like it. What was he doing behind the sofa?

When Phelps wasn’t more than a foot from Marple, he said, his voice oddly deep and pleasant, “Are you awake, Jimbo? Come on, I didn’t hit you that hard, you pathetic wuss.”

Jimbo? Savich turned up the volume on his directional receiver.

“Do you know it will be dawn in another thirty-seven minutes? I’ve decided to kill you at dawn.”

Mr. Marple slowly raised his head. His glasses had slipped down his nose, and with his hands tied behind him, he couldn’t do anything about it. He licked at the dried blood beside his mouth.

“Yes, I’m awake. What do you want, Philly? What the hell is going on here? Why are you doing this?”

Philly? The two men knew each other well enough for nicknames.

Phelps laughed, and Savich felt his skin crawl. It was a mad old laugh, scratchy and black, not at all pleasant and deep like his voice. Phelps pulled a knife from inside his flannel shirt, a long hunting knife that gleamed even in the dull light.

Savich had expected a gun, not a knife. It wasn’t supposed to go down like this. Two dead high school math teachers, and now this. Not in pattern. What was going on here?

“You ready to die, Jimbo, you little prick?”

“I’m not a prick. What the hell are you doing? Are you insane? Jesus, Philly, it’s been over five years! Put down that knife!”

But Mr. Phelps tossed the knife from one hand to the other with easy movements that bespoke great familiarity.

“Why should I, Jimbo? I think I’m going to cut out your brain. I’ve always hated your brain, do you know that? I’ve always despised you for the way you wanted everyone to see how smart you were, how fast you could jigger out magic solutions, you little bastard-” He was laughing as he slowly raised the knife.

“It’s not dawn yet!”

“Yeah, but I’m old, and who knows? By dawn I might drop dead of a heart attack. I really do want you dead before me, Jimbo.”

Savich had already aimed his SIG Sauer, his mouth open to yell, when Jimbo screamed, kicked out wildly, and flung the chair over backward. Phelps dove forward after him, cursing, stabbing the knife through the air.

Savich fired right at the long silver blade. At nearly the same moment there was another shot-the loud, sharp sound of a rifle, fired from a distance.

The long knife exploded, shattering Phelps’s hand; the next thing to go flying was Phelps’s brains as his head exploded. Savich saw his bloody fingers spiraling upward, spewing blood, and shards of silver raining down, but Phelps wouldn’t miss his hand or his fingers. Savich whipped around, not wanting to believe what had just happened.

The sniper, Kurt Cooper, had fired.

Savich yelled “No!” but of course it was way too late. Savich ran to the front door and slammed through, agents and local cops behind him.

James Marple was lying on his back, white-faced, whimpering. By going over backward he’d saved himself from being splattered by Mr. Phelps’s brains.

Marvin Phelps’s body lay on its side, his head nearly severed from his neck, sharp points of the silver knife blade embedded in his face and chest, his right wrist a bloody stump.

Savich was on his knees, untying Jimbo’s ankles and arms, trying to calm him down. “You’re all right, Mr. Marple. You’re all right, just breathe in and out, that’s good. Stay with me here, you’re all right.”

“Phelps, he was going to kill me, kill me-oh, God.”

“Not any longer. He’s dead. You’re all right.” Savich got him free and helped him to his feet, keeping himself between James Marple and the corpse.