Business in need of a quick fix? Find an unwitting victim, cut off a hand, and bury it under your shop's front door.

According to the warped logic of the most extreme of South Africa's traditional beliefs, that hand will "call" customers, and their money, to your shop's doors.

These so-called "muti" murders - killings to obtain body parts for supposedly potent traditional cures - still occur with alarming regularity in post-apartheid South Africa, says Gerard Labuschagne, head of a police unit devoted to investigating the country's most bizarre crimes.

The discovery of a young woman's severed head, floating in a dam near Johannesburg late last month, has fuelled press speculation that the victim was killed for her body parts.

Although police have not confirmed that the killing was connected to muti, the incident has had traditional healers scrambling to denounce the practice.

In London, the arrest of 21 people by police hunting the killers of a young boy whose headless and limbless torso was found in the River Thames has spread the profile of muti killings to a wider audience.

But Labuschagne says such murders often go unreported, apart from a few high-profile cases. Although official statistics are not available, he estimates there are anything between 150 and 300 such killings each year.

"In South Africa it happens fairly regularly; it is occurring at least each month," he said. "For many of the police it is nothing unusual, just treated as a normal murder... So there are a lot of muti-related murders that we are not informed about."

The vast majority of traditional healers, who use herbs, bark and animal remains for their remedies, say they have no dealings with human body parts. However, the strength of a recipe is thought to depend on its composition, and the belief that human parts make the strongest ingredients sometimes tempts less scrupulous practitioners to include them in their concoctions.

"It is definitely wrong to tar all traditional healers, who play an important role in the community, with the same brush," said Labuschagne, adding that the majority condemned muti murders wholeheartedly.

Sitting behind his desk in an office plastered with press cuttings of serial murder cases, Labuschagne says he doesn't lose much sleep investigating these gruesome killings.

But then he is not shocked by depravity - he has a doctorate in clinical psychology and has studied serial killers since 1994.

His unit focuses on some of the country's most unusual crimes. Serial rapists are the main task this year, but mass-murderers, baby-rapists and extortionists all receive his attention.

"But the most out-of-the-ordinary stuff that we investigate are the muti murders," he said.

High-profile cases in recent years have included the discovery of three headless bodies, and three severed heads that did not match them, in lakes and rivers near Johannesburg.

Last year, police arrested a man who was trying to sell a severed head for about R12 000 for use in traditional medicine.

These murders have also attracted huge attention overseas. London detectives have been trying to unravel the mystery surrounding a torso found in the Thames and have turned to West Africa in their search, but their arrest of 21 people late last month grabbed headlines and focused attention on muti killings.

Muti murders are hard to solve because of the number of people involved, Labuschagne says.

He says it is usually quite easy to identify such crimes - body parts are removed in a functional manner while the victim is alive, without any trace of enjoyment by the killer, in contrast to serial or sadistic murders.

A healer will describe to the murderer what parts are needed, and the manner in which they are to be collected: testicles for virility purposes, fat from the breasts or abdomen for luck, tongues to smooth the path to a woman's heart.

"The poor victim usually just happened to fit the bill at that time," Labuschagne said.

However, it is usually hard to pin down healers and clients.

"Often the murderer does not want to inform on the healer for fear of being cursed," he said.

Labuschagne says his unit has little hope of eradicating the practice in the near future.

"For centuries it has been the practice, it is nothing new.

"I don't think anyone can believe ideas that we will stop muti murders occurring, any more than one could say we are going to stop prostitution," Labuschagne said. - Reuters