LONDON - From Rwanda to Cambodia, mass killers may have fallen victim to a deadly

syndrome that turns normal people into callous murderers, according to a research

paper published Dec 19.

Sufferers from so-called "Syndrome E" showed no emotion about killing frequently.

They can spend the day herding children into gas chambers and then return home to

supper with their families.

"The transformation of groups of previously non-violent individuals into repetitive

killers of defenseless members of society has been a recurring phenomenon throughout

history," said Professor Itzhak Fried of the UCLA Medical Center at the University

of California.

Fried, writing in The Lancet science magazine, said this sinister transformation

is characterized by a set of symptoms that suggest a common syndrome.

These repeat killers on a mass scale are obsessed with beliefs directed against minorities.

"Metaphors such as 'cleansing' are often used to justify violence," he

said.

The killers are not seized by a burst of frenzied battlefield emotion. Instead they

kill calmly "with flat effect".

They show no outward signs of acting abnormally and rapidly become desensitized to

the enormity of their crimes, Fried said.

"They may lead a normal family life while in parallel engaging in killing of

families," he wrote.

Fried believed that manifestations of Syndrome E were due to what he called a "cognitive

fracture" between various parts of the brain that determine emotion, mood and

reaction to events.

The neurosurgeon argued that it was vital to isolate victims showing signs of Syndrome

E because their blood lust could be contagious to others who might be similarly.

"Prompt diagnosis would be of paramount importance as prevention may be effective

only in the early stages," he said.