Also on the wall behind Vassileyev’s desk, displayed in a black shadow box, was a cut-throat razor opened halfway to form a V.

“It’s Occam’s razor,” explained Vassileyev.

Pekkala, feeling foolish, admitted that he had not heard of Occam, whom he assumed to be a great criminal put behind bars by Vassileyev’s detective work.

Vassileyev laughed when he heard this. “It’s not really Occam’s razor. The razor is just an idea.” Seeing Pekkala’s confusion, he went on to explain. “In the Middle Ages, a Franciscan monk named William of Occam formulated one of the basic principles of detective work, which is that the simplest explanation that fits the facts is usually right.”

“But why is it called Occam’s razor?” asked Pekkala.

“I don’t know,” admitted Vassileyev. “Probably because it cuts straight to the truth, something you will need to learn how to do if you ever hope to survive as an investigator.”

Vassileyev liked to test Pekkala, sending him into town with instructions to walk a certain route. Vassileyev, meanwhile, would have planted people along the way, noted down advertisements pasted on walls, the headlines of newspapers hawked on the street corners by boys with floppy hats. No detail was too small. When Pekkala returned, Vassileyev would quiz the young man about everything he had seen. The point, Vassileyev explained, was that there was too much to note down, especially when he might not even know what he was looking for. The purpose of the exercise was to train Pekkala’s mind to catalogue it all and then to permit his subconscious to sift through the information. Eventually, Vassileyev explained, he would be able to rely solely on his instincts to tell him when something was not right.

Other times, Pekkala was instructed to evade capture by traveling in disguise across the city while different agents searched for him. He learned to pose as a cabdriver, a priest, and a bartender.

He studied the effects of poisons, the disarming of bombs, the business of killing with a knife.

In addition to instructing Pekkala on how to shoot a variety of weapons, all of which he had to disassemble, reassemble, and load while blindfolded, Vassileyev taught him to recognize the sounds made by different-caliber guns and even the varying sounds made by different models of the same caliber. Pekkala would sit on a chair behind a brick wall while Vassileyev, perched on a chair on the other side of the wall, fired off various guns and asked Pekkala to identify each one. During these sessions, Vassileyev was rarely without a cigarette wedged between his wooden fingers. Pekkala learned to watch the thin gray line of smoke rising from behind the wall, and the way it would ripple as Vassileyev bit down on the cigarette, just before he pulled the trigger of the gun.

At the beginning of his third year of training, Vassileyev called Pekkala into his office. The artificial leg was on the desk. Using a chisel, Vassileyev had begun to hollow out the solid block of wood from which his prosthetic limb had been constructed.

“Why are you doing that?” Pekkala asked.

“Well, you never know when you might need a hiding place for valuables. Besides, this damned thing is too heavy for me.” Vassileyev set down the chisel and carefully swept the wood shavings into his palm. “Do you know why the Tsar chose you for this job?”

“I never asked him,” replied Pekkala.

“He told me that he chose you because you have the closest thing to perfect memory as he has ever seen. And also because you are a Finn. To us Russians, the Finns have never quite seemed human.”

“Not human?”

“Warlocks. Witches. Magicians,” explained Vassileyev. “Do you know that many Russians still believe the Finns are capable of casting spells? That’s why the Tsar surrounded himself with a regiment of Finnish Guards. And that is why he picked you. But you and I both know that you are not a magician.”

“I never claimed to be one.”

“Nevertheless,” replied Vassileyev, “that is how you are likely to be seen, even by the Tsar himself. You must not forget the difference between who you are and who people believe you to be. The Tsar needs you even more than he realizes. Dark times are coming, Pekkala. Back when I got blown to bits, crooks were still robbing money from banks. Now they have learned how to steal the whole bank. It won’t be long before they are running the country. If we let them get that far, Pekkala, you and I will wake up one day and find we are the criminals. And then you’ll need the skills I’ve taught you just to stay alive.”

THE NEXT MORNING, AS RED STREAMERS OF DAWN UNFURLED ACROSS the sky, Pekkala, Kirov, and Anton climbed into the Emka staff car.

The houses all around were still shuttered, their occupants not yet emerged. The slatted shutters made the buildings look as if they were asleep, but there was something sinister about them, and each man felt that he was being watched.

Kirov got behind the wheel. Having stayed up half the night reading the secret report, the young Commissar now seemed in a state of total shock.

Pekkala had decided that they should proceed directly to the mine shaft where the bodies had been dumped. According to Anton, who had the place marked on his map, the mine was on the outskirts of Sverdlovsk, approximately two days’ drive away.

They had only been on the road a few minutes when a figure came stumbling out of an abandoned house on the outskirts of the town. It was the policeman. His clothes were filthy from hiding out all night.

The Emka skidded to a stop.

The policeman stood ankle deep in a puddle in the middle of the road. He was drunk. He moved like a man on the deck of a ship in rough seas. “I don’t care if he’s the Emerald Eye or not!” he shouted. “You’re taking me with you.” He staggered over to the car, hauled out his service revolver, and tapped the glass with the barrel of the gun.

“Everybody out,” said Anton, in a low voice.

The three men piled into the muddy road.

“We have to get out of here!” shouted the policeman. “Word is all over town that Pekkala is investigating me!” He brandished the gun back towards the rooftops of the village. “But they’re not going to wait for that.”

“We have more important things to do than put you under investigation,” said Anton, not taking his eyes from the gun.

“It doesn’t matter now!” insisted the policeman. “If I go back into town, those people will tear me to pieces!”

“You should have thought about that,” said Anton, “before you started kicking the teeth out of old men. Your job is to stay at your post. Now get out of the road and go back to work.”

“I can’t.” The policeman’s finger locked inside the trigger guard. All he had to do was clench his hand and the gun would go off. The way the man looked, he seemed just as likely to accomplish that by accident as on purpose. “I won’t let you leave me here!”

“I will not help you to desert,” replied Anton.

“I wouldn’t be deserting!” His voice rippled thinly through the still morning air. “I could come back with reinforcements.”

“I can’t help you,” said Anton. “We have other work to do.”

“This is your fault! You brought that ghost into my town”-he jerked his head towards Pekkala-“and woke up things which should have stayed asleep.”

“Return to your post,” Anton ordered. “You are not coming with us.”

The policeman trembled, as if the ground beneath his feet were shaking. Then suddenly his arm swung out.

Anton found himself staring down the blue eye of a gun barrel. His holster was strapped to his waist, but he would never be able to reach it in time. He stood motionless, hands by his sides.

“Go on,” the policeman challenged. “Give me an excuse.”

Now Kirov grabbed for the flap of his holster, drew the gun, but lost his grip on the handle. The pistol slipped through his fingers. Kirov ’s empty hands clawed at nothing as the Tokarev cartwheeled into the mud. A look of terrified amazement spread across his face.