The museum had a catacomb’s low ceiling and compressed atmosphere. Unlit dioramas were spaced down the walls like abandoned chapels. At the far end, instead of an altar, open crates held unpolished plaques and dusty flags.

Arkady remembered the first time he had been granted admittance twenty years before, and the ghoulish eyes and sepulchral tone of his elderly guide, a captain whose only duty was to instill in visitors the glorious heritage and sacred mission of the militia. He tried the light switch on a display. Nothing.

The next switch did work and illuminated a foreshortened Moscow street circa 1930 with the hearselike cars of that period, model figures of men striding importantly, women shuffling with bags, boys hiding behind lampposts, all apparently normal except for, lurking on the corner, a doll with his coat collar turned up to his hat brim, a miniature paranoid. “Can you find the undercover officer?” the captain had proudly asked.

The younger Arkady had arrived with other high school boys, a group picture of sniggering hypocrisy. “No,” they chorused with a straight face while they traded smirks.

Two more dead switches, then a scene of a man skulking into a house to reach for an overcoat hanging in the foyer. In an adjoining parlor a plaster family listened contentedly to the radio. A caption revealed that when this “master criminal” was captured he had a thousand coats in his possession. Wealth beyond compare!

“Can you tell me,” the captain had asked, “how this criminal, without drawing suspicion, carried these coats home? Think before you answer.” Ten blank faces stared back. “He wore them.” The captain looked each boy in the eye so that everyone understood the sheer brilliance and inventive deceit of the criminal mind. “He wore them.”

Other models continued the historical survey of Soviet crime. Not a tradition of subtlety, Arkady thought. See photos of slaughtered children, see the ax, see the hair on the ax. Another display of disinterred bodies, another murderer with a face half-erased by a lifetime of vodka consumption, another carefully preserved ax.

Two scenes in particular were designed to draw gasps of horror. One was of a bank robber who made his getaway in Lenin’s car, equal to stealing an ass from Christ. The other featured a terrorist with a homemade rocket that had narrowly missed Stalin. Find the crime, Arkady thought: trying to kill Stalin or missing him.

“Don’t dwell in the past,” Rodionov said from the door. The city prosecutor delivered his warning with a smile. “We’re the men of the future, Renko, all of us, from now on.”