By Tristana Moore
BBC News, Berlin
It is an extraordinary case which has baffled German detectives for the last 15 years.
German police say they could be closer to uncovering the identity of a female killer who has left a trail of her DNA all over Germany, Austria and France.
Is this the Phantom of Heilbronn?
The suspect, known as the Phantom of Heilbronn, is wanted in connection with 30 crimes, including six murders and dozens of robberies.
Police have no idea what she looks like, they do not know how old she is, but they have one big clue - her DNA.
The mysterious killer is also a suspect in the murder of a 22-year-old police officer, Michele Kiesewetter, who was shot dead in a car park in the western German city of Heilbronn on 25 April 2007.
Her colleague was seriously injured in the shooting. Investigators say samples of the suspect's DNA were discovered in the murdered officer's patrol car at the crime scene.
In a new twist, German police have now issued a photo-fit picture of a man, who could be the suspect, or an accomplice.
So is the Phantom of Heilbronn a man or a transsexual?
Eyewitnesses are reported to have seen this person at the scene of an attempted break-in at a flat in another German city, Saarbruecken, in 2006.
Traces of DNA belonging to the "Phantom" were found on a stone at this crime scene.
"We can't rule out that our suspect is a man now - or that she looks like a man. We just don't know," said Rainer Koeller, a police spokesman.
The first genetic traces of the suspect were discovered in May 1993. A woman was found strangled in Idar-Oberstein.
Since then, there has been a spate of break-ins, robberies and murders.
The killer's latest victims could have been three Georgian car dealers whose bodies were fished out of a river in February, near Heppenheim, in the German state of Hesse.
Police in Heppenheim have two suspects in this case, a Somali man and an Iraqi man.
Oddly enough, police say DNA samples of the mysterious killer have been found in an old white Ford car belonging to the Iraqi suspect.
"This is a unique case. We have 30 crime scenes where we have found traces of her DNA, but we have no face,"
says Mr Koeller.
"It's a huge mystery and it's incredible that the suspect has managed to hide herself for so long."
In Austria, there are DNA traces linking the woman to 16 crime scenes.
German detectives have travelled across Europe, questioning witnesses, and are investigating new leads.
Since last summer, the suspect has broken into lots of garden sheds in the state of Baden-Wuerttemberg, once again leaving a DNA trail.
Investigators believe that she spent the night in some of these sheds and stole food and drinks.
German police are warning that the suspect is armed and dangerous and they are urging people to be vigilant.
The authorities have offered a reward of 100,000 euros (£80,000) for information leading to the arrest of the elusive killer.