The roll call of victims is growing longer by the day. They have names like Rocco, Fussel, Marianne and Fluffy — and a five-man police unit has a file on each and every one. The so-called “bunny murders” — 40 domestic rabbits killed at night in their hutches, heads and sometimes paws sliced off, their bodies drained of blood — is stunning communities across western Germany.

“Nobody knows where the killer will strike next,” said Inspector Volker Schütte. One theory is that a group of Satanists is behind the wave of killings, because there is an almost ritualistic pattern. Amputated paws have been placed on doorsteps; the blood may have been drained into phials for use in an initiation ceremony.

So far, inquiries in Satanist and cultist groups have turned up little — but a child’s coffin and a red velvet cloth were found recently near the scene of the rabbit killings. The coffin was empty but there was rabbit hair on the cloth.

The main concern is that whoever is killing rabbits may go on to kill humans. “Sadists often begin with violence against animals,” said Mark Benecke, a criminal psychologist who has been advising the police since the killings began last year. “Perpetrators like this are sexually aroused by seeing their victims suffer.”

The psychotherapist Christian Lüdke agreed that there was reason to be worried. “He takes pleasure in killing and wants power over life and death,” said Mr Lüdke, who specialises in serial killers.

Few countries are as sensitive to animal cruelty as Germany. Even the Nazis, while putting into place a system to mass murder the Jews, introduced some of the toughest animal-protection laws in the world. Vivisection was banned. Hermann Goering, Hitler’s henchman, announced that vivisectors would be held in concentration camps until they were put on trial; the Nazis regulated the shoeing of horses, the boiling of lobsters and even the cutting up of frogs for bait. As the war wore on, the Nazis tolerated the keeping of rabbits on balconies to supplement meat rations — but it remained a highly sensitive issue. And after the war, local rabbit breeders’ associations became a huge movement.

Little wonder then that the full resources of the police are being deployed. DNA samples are being taken from the mutilated rabbits. There are no witnesses, so the team of detectives has been unable to issue an Identikit picture, but it has developed a sophisticated networking analysis linking all the rabbit breeders who have been affected so far. Did they have a common vet? Have there been feuds within the rabbit-breeding community? Was the timing of the attacks, nearly 20 of them, linked to competition show dates?

About 300 breeders have been interviewed so far but the police still seem to be stumbling in the dark. The assumption is that the killer is male, computer-literate — he seems to have identified houses with backyard rabbit hutches by using Google Earth — and living locally.

All the attacks have taken place in the Ruhr Valley, an industrial area better known for domestic breeding of carrier pigeons than of rabbits. But as the coalmines have shut, the pet ownership patterns of the workers have also changed. Some of the rabbits are being bred for competition, some as pets; rarely, if ever, are they slaughtered for meat.

Dortmund and Witten are the main targeted areas and the police have composed a “mind map” linking the streets involved.

Almost a decade ago, there were dozens of cases of horses being maimed or decapitated in Lower Saxony. The criminals were never found. This time the chances are better because this is an urban crime wave, committed in the gardens of close-packed terrace houses.

“Sooner or later a witness will emerge,” said a detective on the team. “We now have enough people on the ground.” Animal rights groups have offered a reward of ¤2,500 (£2,000) for tips leading to an arrest.

Meanwhile, the nervous breeders of the Ruhr are shifting their rabbits into safe houses: hutches are being set up in cellars or in secluded garden allotments away from the main house. Locks and alarm systems are now the norm.

“Any one of us could be next on the hit list,” said Horst Hauschka, 65, a breeder from Dortmund.

Some breeders are setting up a neighbourhood watch system. But there is the nagging fear that the killer may not be the psychopathic loner being hunted by the police, but rather one of their own community; a breeder with a dark secret.

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