And there was something else, the instinct that propelled him out of bed every morning into each unwelcoming day, and that was the desire to know. In police work, there was always another junction to reach, another corner to peer around. Who were the Weiss family, and what had happened to them? Whose was the body in the lake? What linked the deaths of Buhler and Stuckart? It kept him going, his blessing or his curse, this compulsion to know. And so, in the end, there was no choice.

He tossed the paper cup into the waste bin, and went upstairs.

Walther Fiebes was in his office, drinking schnapps. Watching him from a table beneath the window was a row of five human heads — white plaster casts with hinged scalps, all raised like lavatory seats, displaying their brains in red and grey sections — the five strains which made up the German Empire.

Placards announced them from left to right, in descending order of acceptability to the authorities. Category One: Pure Nordic. Category Two: Predominantly Nordic or Phalic. Category Three: Harmonious Bastard with Slight Alpine Dinaric or Mediterranean Characteristics. These groups qualified for membership of the SS. The others could hold no public office and stared reproachfully at Fiebes. Category Four: Bastard of Predominantly East-Baltic or Alpine Origin. Category Five: Bastard of Extra-European Origin.

March was a One/Two; Fiebes, ironically, a borderline Three. But then, the racial fanatics were seldom the blue-eyed Aryan supermen — they, in the words of Das Schwarzes Korps, were “too inclined to take their membership of the Volk for granted”. Instead, the swampy frontiers of the German race were patrolled by those less confident of their blood-worthiness. Insecurity breeds good border guards. The knock-kneed Franconian schoolmaster, ridiculous in his Lederhosen; the Bavarian shopkeeper with his pebble glasses; the red-haired Thuringian accountant with a nervous tic and a predilection for the younger members of the Hitler Youth; the lame and the ugly, the runts of the national litter — these were the loudest defenders of the Volk.

So it was with Fiebes — the myopic, stooping, buck-toothed, cuckolded Fiebes — whom the Reich had blessed with the one job he really wanted. Homosexuality and miscegenation had replaced rape and incest as capital offences. Abortion, “an act of sabotage against Germany’s racial future”, was punishable by death. The permissive 1960s were showing a strong increase in such sex crimes. Fiebes, a sheet-sniffer by temperament, worked all the hours the Fuhrer sent and was as happy, in Max Jaeger’s words, as a pig in horseshit.

But not today. Now, he was drinking in the office, his eyes were moist, and his bat’s-wing toupee hung slightly askew.

March said: “According to the newspapers, Stuckart died of heart failure.” Fiebes blinked.

“But according to the Registry, the file on Stuckart is out to you.”

“I cannot comment.”

“Of course you can. We are colleagues.” March sat down and lit a cigarette. “I take it we are in the familiar business of "sparing the family embarrassment".”

Fiebes muttered: “Not just the family.” He hesitated. “Could I have one of those?”

“Sure.” March gave him a cigarette and flicked his lighter. Fiebes took an experimental draw, like a schoolboy.

“This affair has left me pretty well shaken, March, I don’t mind admitting. The man was a hero to me.”

“You knew him?”

“By reputation, naturally. I never actually met him. Why? What is your interest?”

“State security. That is all I can say. You know how it is.”

“Ah. Now I understand.” Fiebes poured himself another large helping of schnapps. “We’re very much alike, March, you and I.”

“We are?”

“Sure. You’re the only investigator who’s in this place as often as I am. We’ve got rid of our wives, our children — all that shit. We live for the job. When it goes well, we’re well. When it goes badly…’His head fell forward. Presently, he said: “Do you know Stuckart’s book?”

“Unfortunately, no.”

Fiebes opened a desk drawer and handed March a battered, leather-bound volume. A Commentary on the German Racial Laws. March leafed through it. There were chapters on each of the three Nuremberg Laws of 1935: the Reich Citizenship Law, the Law for the Protection of German Blood and German Honour, the Law for the Protection of the Genetic Health of the German People. Some passages were underlined in red ink, with exclamation marks beside them. “For the avoidance of racial damage, it is necessary for couples to submit to medical examination before marriage.”

“Marriage between persons suffering from venereal disease, feeble-mindedness, epilepsy or ‘genetic infirmities’ (see 1933 Sterilisation Law) will be permitted only after production of a sterilisation certificate.” There were charts: “An Overview of the Admissibility of Marriage between Aryans and non-Aryans”, The Prevalence of Mischling of the First Degree”.

It was all gobbledygook to Xavier March.

Fiebes said: “Most of it is out of date now. A lot of it refers to Jews, and the Jews, as we know” — he gave a wink — “have all gone east. But Stuckart is still the bible of my calling. This is the foundation stone.”

March handed him the book. Fiebes cradled it like a baby. “Now what I really need to see”, said March, “is the file on Stuckart’s death.”

He was braced for an argument. Instead, Fiebes merely made an expansive gesture with his bottle of schnapps. “Go ahead.”

THE Kripo file was an ancient one. It went back more than a quarter of a century. In 1936, Stuckart had become a member of the Interior Ministry’s “Committee for the Protection of German Blood” — a tribunal of civil servants, lawyers and doctors who considered applications for marriage between Aryans and non-Aryans. Shortly afterwards, the police had started receiving anonymous allegations that Stuckart was providing marriage licences in exchange for cash bribes. He had also apparently demanded sexual favours from some of the women involved.

The first name complainant was a Dortmund tailor, a Herr Maser, who had protested to his local Party office that his fiancee had been assaulted. His statement had been passed to the Kripo. There was no record of any investigation. Instead, Maser and his girlfriend had been dispatched to concentration camps. Various other stories from informants, including one from Stuckart’s wartime Block-wart, were included in the file. No action had ever been taken.

In 1953, Stuckart had begun a liaison with an eighteen-year-old Warsaw girl, Maria Dymarski. She had claimed German ancestry back to 1720 in order to marry a Wehrmacht captain. The conclusion of the Interior Ministry’s experts was that the documents were forged. The following year, Dymarski had been given a permit to work as a domestic servant in Berlin. Her employer’s name was listed as Wilhelm Stuckart.

March looked up. “How did he get away with it for ten years?”

“He was an Obergruppenfuhrer, March. You don’t make complaints about a man like that. Remember what happened to Maser when he complained? Besides, nobody had any evidence — then.”

“And there is evidence now?”

“Look in the envelope.’”

Inside the file, in a manila envelope, were a dozen colour photographs, of startlingly good quality, showing Stuckart and Dymarski in bed. White bodies against red satin sheets. The faces — contorted in some shots, relaxed in others — were easy to identify. They were all taken from the same position, alongside the bed. The girl’s body, pale and undernourished, looked fragile beneath the man’s. In one shot she sat astride him — thin white arms clasped behind her head, face tilted towards the camera. Her features were broad, Slavic. But with her shoulder-length hair dyed blonde she could have passed as a German.