Does someone who mutilates or tortures animals have the sadistic urge to harm people? Criminal psychologists in Germany certainly believe so — and the scientific literature seems to bear them out.

Christian Lüdke, an expert on serial murder, said: “The risk that he will use violence against people is enormous.”

Dr Lüdke believes that the rabbit killer is male, between 25 and 45, with serious behavioural disorders. “He takes the rabbits’ heads with him after decapitation to prolong the pleasure of the killing. He enjoys killing, the power over life and death.”

Studies in the United States bear this out. Kathleen Quinn, a psychologist and expert on domestic violence, says that cruelty to animals is one of the childhood features linking killers such as Jeffrey Dahmer and Ted Bundy.

“Animal cruelty, which begins showing up as early as the age of 6, is one of the earliest and most reliable predictors of later violent behaviour,” she writes.

Research in the 1960s turned up three indicators of future violence: setting fires, childhood bed-wetting past the age of 5 and animal abuse. Taken together, and occurring in households with alcoholic fathers, these were danger signals. Later testing found this to be true if the cruelty had been inflicted on valued animals, such as pet dogs, rather than on rodents.

“Children in violent homes often rely more on their pets for love and loyalty than do other children,” says Dr Quinn. “Yet in violent homes, animals seldom survive past age 2 — they are either killed, die from neglect or run away to escape the abuse.”

The side-effect is that the young child suffers from repeated cycles of attachment and loss. A New Jersey study showed that in physically abusive families pets were mistreated as a way of hurting another family member. These patterns often crop up in the biographies of serial killers as well as child abusers.

Reason enough to take the bunny murders seriously.

Times Recommends

• Would you live on the wrong side of the Berlin Wall?
• Wish you were here, says Iraq tourist board
• Russian policeman’s corruption plea to Putin