The cannibal says his victim volunteered to be slaughtered. The man confessed after police thwarted his attempt to find a new victim over the internet: at least five men had already declared their willingness to be eaten.

The tabloid daily Bild expressed concern that cannibals could be roaming German streets. “They are invisible behind their glasses, their hairstyles, their families, their work, their seemingly unblemished innocence,” wrote Franz Josef Wagner, a columnist for the paper. “These sick people are hiding among us, they are in our very midst.”

Cannibalism not only breaches moral and social taboos, it hits a nerve for a whole generation of Germans who remember the desperate eating of human organs during the Nazi invasion of the Soviet Union.

Bodies of fallen soldiers frozen in the snow sometimes had to provide meat for the half-starved Wehrmacht in retreat.

The three months of hand-to-hand fighting in the icy ruins of Stalingrad during the winter of 1942-3 saw — as German veterans now admit — a frenzied resort to human flesh. After the war, when the soldiers started to trickle back from Soviet captivity, some of the horrific stories were passed on to families.

For German literature however wartime cannibalism remained a forbidden subject. This latest case of cannibalism plainly stems from sexual perversion. But the ghost of wartime hunger and the buried secrets of a generation hung over the public debate yesterday.

The victim of the ritualistic killing was a 42-year-old leading microchip designer at the electronics giant Siemens, one of the best according to his colleagues. Bernd Jürgen B (his surname has been withheld) was a slim, athletic chainsmoker who lived in a luxurious penthouse suite decked out with £30,000-worth of cutting-edge computer equipment. He disappeared in the spring of 2000 after having first sold his Mitsubishi car and some other valuables.

Police now know that he responded to an internet advertisement announcing: “Wanted: young, well-built 18-30-year-old for slaughter.”

The man who placed the advertisement — and who started to advertise again this year — was Armin M (surname withheld) from the charming half-timbered town of Rotenburg in the western state of Hesse.

The 41-year-old computer technician was entirely serious: investigators this week found a slaughtering room, complete with meat hooks, in his apartment. Herr M, a former sergeant major in the German army who later worked for the council in Mainz, video-recorded his butchery.

Police have confiscated 50 videos which are said to be worth thousands on the very specialised market for cannibal acts. Details from the confessions of Armin M were published in all German newspapers yesterday.

He says that he and the victim fried and ate part of the victim’s body before leaving the kitchen for the slaughtering room, where Herr M switched on the camera and then stabbed Herr B to death. He hung the body upside down on a meat hook to allow the blood to drain and later sliced it into small chunks, which he wrapped and stored in the deep-freeze.

Herr M has been eating Herr B ever since; some pieces were found in the freezer this week. He buried inedible body parts and bones in a garden. These too have been recovered by the police.

Germany is struggling to understand the act. The head of the Criminological Institute in Wiesbaden, Dr Rudolf Egg, said that modern cannibals use deep-freezing to extend and ration out their pleasure. Primitive cannibals used to eat their victims all at one go soon after killing.

“If he really derived pleasure from eating a man,” he said, “then he could not possibly eat everything in a single day. And he obviously did not want to eat rotten meat. So he froze the body parts; the act of eating then took on the aspect of a ritual and could be drawn into his sexual fantasies.”

Franz Josef Wagner blamed the case on the film The Silence of the Lambs and its prequel, Red Dragon, released this year. “The cult star of the film world in 2002 was Hannibal Lecter, who ate a human brain to the music of Vivaldi.”

Since the information about the case comes solely from the confessing killer, police are unsure whether Herr B really did co-operate in his own consumption. The cannibal has been charged with murder.

In recent months Herr M has placed 80 advertisements calling for new victims. The five men who replied appear to have been genuine volunteers but police were unwilling to disclose details yesterday.

As far as the investigators can work out, Herr M has so far committed only one act of cannibalism but inquiries are being extended to other places where he lived and worked.

“This is going to take a while,” said the state prosecutor of Cassel, Hans-Manfred Jung.

The savages