"I swear to God!" Marquez muttered. "We left two dead bodies, an unconscious killer, and Dr. Ambrose with a gun to cover him."

Pitt ignored the sheriff and dropped to his knees. He swept his light around the tunnel very slowly in a 180-degree arc, his eyes examining every inch of the ground and the ore car tracks.

Marquez started to say, "What are you-?" but Pitt threw up one hand, motioning him to silence.

In Pitt's mind, if Ambrose and the killer were gone, they had to have left some tiny indication of their presence. His original intent had been to look for the shell casings ejected from the P-10 automatic he'd used to shoot the killers. But there was no hint of a gleam from the brass casings. The back of his neck began to tingle. This was the right spot, he was certain of it. Then he sensed rather than saw an almost infinitesimal strand of black wire no more than eighteen inches away, so thin it didn't cast a shadow under his light. He trailed the beam along the wire, over the rail tracks, and up the wall to a black canvas bundle attached to one of the overhead timbers.

"Tell me, Sheriff," Pitt said in a strangely quiet voice, "have you had bomb-disposal training?"

"I teach a course in it to law enforcement," Eagan replied, eyebrows raised. "I was a demolitions expert in the Army. Why ask?"

"I do believe we were set up to enter the next world in pieces." He pointed to the wire leading from the tracks and up the timber. "Unless I miss my guess, that's an explosive booby trap."

Eagan moved until his face was inches away from the black strand. He followed it up to the canvas bundle and studied the bundle carefully. Then he turned to Pitt with a new level of respect in his eyes. "I do believe you are right, Mr. Pitt. Somebody doesn't like you."

"Include yourself, Sheriff. They must have known you and your men would have accompanied us back to Dr. Ambrose."

"Where is the professor?" wondered Marquez aloud. "Where did he and the killer go?"

"There are two possibilities," said Pitt. "The first is that the killer regained consciousness, overpowered Doc Ambrose, killed him and dumped his body down the nearest mine shaft. Then he placed the charge and escaped through another tunnel leading to the outside."

"You should write fairy tales," said Eagan.

"Then explain the booby trap."

"How do I know you didn't set it?"

"I have no motive."

"Get off it, Jim," said Marquez. "Mr. Pitt hasn't been out of my sight for the past five hours. He just saved our lives. If the blast didn't get us, the cave-in would."

"We're not certain the bundle contains explosives," Eagan said stubbornly.

"Then trip the wire and see what happens." Pitt grinned. "I, for one, am not going to hang around and find out. I'm out of here." He rose to his feet and began strolling along the ore car tracks back to the hotel.

"One moment, Mr. Pitt. I'm not through with you."

Pitt paused and turned. "What are your intentions, Sheriff?"

"Check out the sack wired to the timber, and if it's an explosive device, disarm it."

Pitt took a few steps back, his face dead serious. "I wouldn't if I were you. That's not some bomb built in the backyard of a junior terrorist. I'll bet my next paycheck it was exactingly assembled by experts and will burst at the slightest touch."

Eagan looked at him. "If you have a better idea, I'd like to hear it."

"The ore car sitting a couple of hundred yards up the track," replied Pitt. "We give it a shove and let it roll through here and trip the wire and detonate the explosives."

"The roof of the tunnel will collapse," said Marquez, "blocking it forever."

Pitt shrugged. "It's not like we're destroying the tunnel to deny access to future generations. We're the first to have passed through this section of the mine since the nineteen-thirties."

"Makes sense," Eagan finally agreed. "We can't leave explosives laying about for the next underground explorers who walk through here."

Fifteen minutes later, Pitt, Eagan, Marquez, and the deputy had pushed the ore car to within fifty yards of the trip wire. The heavy iron wheels squeaked and protested for the first fifty feet, but soon loosened and began to roll smoothly over the rusty rails as the ancient grease on their axles lubricated the roller bearings. The four sweating men finally reached the crest of a slight slope that led downward.

"The end of the line," Pitt announced. "One good shove and she should roll for a mile."

"Or until she drops into the next shaft," said Marquez.

The men heaved in unison and ran with the car, propelling it until it picked up speed and began to outrace them. They staggered to a halt and caught their breath, allowing their pounding hearts to slow. Then they held their flashlights on the ore car as it charged over the rails and disappeared around a gradual curve of the tunnel.

Less than a minute later, a tremendous detonation tore through the tunnel. The shock wave nearly knocked them off their feet. Then came a cloud of dust that swirled around and past them, followed by the deep rumble of tons of rock falling from the roof of the tunnel.

The rumble was still ringing in their ears, the echoes reverberating in the old mine, when Marquez shouted to Eagan, "That should stifle any doubts."

"In your haste to prove your point, you overlooked something," Eagan said loudly, his tone dry and provocative.

Pitt looked at him. "Which is?"

"Dr. Ambrose. He could still be alive somewhere beyond the cave-in. And even if he's dead, there will be no way of retrieving his body."

"It'll be a wasted effort," Pitt said briefly.

"You only gave us one possibility," said Eagan. "Does this have something to do with the second?"

Pitt gave a slight nod. "Dr. Ambrose," he said patiently, "is not dead."

"Are you saying the third assassin didn't kill him?" asked Marquez.

"He'd hardly murder his own boss."

"Boss?"

Pitt smiled and said firmly, "Dr. Tom Ambrose was one of the killers."

"Forgive me for arriving late for dinner," said Pat as she stepped through the Marquezes' front door. "But I desperately needed a hot bath, and I fear I soaked too long."

Lisa Marquez hugged Pat joyously. "You don't know how happy I am to see you again." She stepped back, and her face lit up like an angelic cherub as she saw Pitt following Pat into the house. She kissed him on both cheeks. "How can I ever thank you for bringing my husband home alive and well?"

"I cheated," Pitt said, with his trademark grin. "To save Luis I had to save myself."

"You're just being modest."

Pat was surprised to see Pitt show a hint of genuine embarrassment as he stared down at the carpet. She added, "Your husband wasn't the only life Dirk saved."

"Luis has been very closemouthed about your ordeal. You must fill me in on the details over dinner." Lisa looked elegant in a designer slacks outfit. "Here, let me take your coats."

"Do I smell elk sizzling on the barbecue?" said Pitt, extricating himself from an awkward situation.

"Luis is in the garage playing with his smoker," said Lisa. "It's too cold to eat outside, so I've set the table inside our glass-enclosed solarium on the rear porch deck. Luis installed heaters, so it's cozy warm. Help yourself to a beer as you pass through the kitchen."