GERMAN police have stepped up the hunt for a murderer dubbed "the woman without a face", who is believed to be a rare female multiple killer.
The mystery woman is suspected of six murders and 15 years of burglaries in three countries. Her latest victims may be three Georgian second-hand car dealers shot execution-style.
The unparalleled inquiry is based entirely on DNA found in smudges of sweat and nearly invisible flakes of shed skin at the crime scenes.
Police in the south-western city of Heilbronn have no idea of the woman's name, appearance or age, hence her nickname. But, should she ever be caught, police can link her to the genetic material in their labs.
One reason for the intensity of the hunt is that police want to avenge one of their own. She is suspected of the cold-blooded murder of a German policewoman, Michele Kiesewetter, 22, in a car park in April last year.
Police believe that the officer approached her and she panicked, killing her with a bullet in the face.
The first genetic traces of the offender were collected at the scene of a crime in May 1993.
A retired woman, 62, was found strangled in her home in Idar-Oberstein, not far from Heilbronn, in what seemed to have been a burglary that had turned violent.
In March 2001, the killer struck again in Freiburg, southwest Germany, this time strangling a 61-year-old man.
Other crime-scene clues include a disposable syringe found in October 2001 in a car park. The blood on it was the suspect's. The contents had been a cocktail of drugs with which she had injected herself.
In a burgled caravan, police discovered she had nibbled a biscuit. A smudge of spit on a toothmark in the remaining fragment of biscuit proved once again to have left a genetic clue.
In autumn 2004, the woman went to the Austrian Tyrol. She broke into garden sheds along the road towards Innsbruck, discarding a pair of tracksuit bottoms, a hooded cardigan and other items.
The killer's DNA has also been found at burglary scenes in France.
Police said yesterday that the woman has left DNA at the scenes of six murders and 24 break-ins. The murders all took place in Germany.
Knowing her dress style, her drug use and cold-bloodedness, police went on television in April 2005 with an appeal to the public for tips, but to no avail.
What galls police is that her criminal career has been gradually getting more ruthless.
After last year's unexplained murder in Heilbronn of the uniformed policewoman, who had briefly worked as an undercover agent, the offender's DNA was found on the police car.
A policeman who was seriously injured in the same attack woke from a coma with no memory of the female assailant, who had pulled a gun and shot the two officers at close range.
This year, police found a few cells of her skin after they stripped and analysed all the upholstery, carpets and lint from the car of a man whom they are holding on suspicion of triple murder.
The man, a former paid police informant, was suspected of killing the three Georgian car dealers, who had come to Germany to buy second-hand cars. Their bodies were dumped in a river at the end of January.
The suspect denies the charge, saying the killer was another man, an Islamic radical from Somalia who is also in police custody – and he denies any knowledge of "the woman without a face". However, her DNA was found in the car, triggering a new theory that she was the men's killer.
Police are compiling a thorough history of the car: who owned it and where it has been seen.
They already know that the three Georgians were driven in the car to Heppenheim, the town where they were killed.
Oddly enough, the car was in police ownership at the time. The criminal investigation department bought it second-hand last year and loaned it to the informant when he was hired to brief police on the activities of his criminal associates.
Erwin Hetger, the police chief of Baden-Wrttemberg state, was jubilant at the find, calling it a "down-payment" for police to solve the case of the mysterious and elusive killer.
"We're closing in on her," Mr Hetger said.