Police detectives across Europe called her “The Woman Without a Face.” She’d murdered at least six people and committed some two dozen lesser crimes in three countries.
In 1993, a 62-year-old German woman was strangled. The only clue was an unknown woman’s DNA found on the rim of a tea cup.
Over the next decade, the same DNA was found on a rock used by a robber to break a window, on a partially-eaten biscuit at another break-in and in a vandalized shed in the Austrian Tyrol.
Nothing more than trace DNA evidence was ever found, leading to the theory that the female phantom always wore gloves. Of her name, age and appearance, police had no clue.
The DNA turned up in 2001 at the scene of a 61-year-old German man’s murder. It was also found on a syringe discarded in a parking lot. The possibility of a drug-addicted serial killer loomed.
DNA from 3,000 female drug users who’d committed serious crimes was tested, but none matched.
In 2007, a police woman in Heilbronn, Germany, was fatally shot in the head. Her partner, who’d also been shot, survived in a coma. When he woke, he couldn’t remember the attack.
The mystery woman’s DNA was found on the patrol car, and investigators started calling her the “Phantom of Heilbronn.”
In 2008, a former police informant was arrested in the deaths of three men from the Republic of Georgia who’d been murdered and dumped in a river. Detectives found the now-familiar DNA in the informant’s car.
The car was owned by the police agency’s criminal investigation department. They’d loaned it to the informant so he could spy on his criminal associates.
The arrestee blamed the murders on a Somali Islamist and denied any knowledge of a female mystery killer, but the police chief expressed confidence. “We’re closing in on her,” he said.
Others were less sure. Crimes attributed to the Woman Without a Face were so wide-ranging and patternless. And nothing the police tried had worked. They issued statements begging the public for help but learned nothing. Authorities offered rewards up to 3 million euros but had no takers.
In 2009, French police sought to identify the charred body of a male asylum-seeker. His DNA tested as female and matched that of the unknown killer. The bizarre result forced investigators to consider the unthinkable.
They’d spent millions of euros and tens of thousands of man-hours chasing a female serial killer while ignoring other potential suspects. What if their suspect didn’t exist?
Eventually, their worst fears were confirmed. All the cotton swabs used to collect DNA evidence in cases linked to the phantom killer came from a German medical company that supplied police in several European countries. The woman sought in what the British newspaper The Independent described as “one of the longest and most perplexing wild-goose chases in criminal history” was a company employee. During the manufacturing process, her DNA contaminated the swabs.
“This is a very embarrassing story,” said German police spokesman Josef Schneider.
Over the last decade, DNA-sequencing techniques have evolved to detect the amount of DNA contained in just a few cells. As the amount of DNA needed for detection lessens, the possibility of contamination by police investigators, medical examiners, laboratory workers and anybody else who handles criminal evidence increases.
I’ll bet traces of my DNA exist as a contaminant in quite a few of the autopsy specimens I collected over the last 30 years.
Dr. Carol J. Huser, a forensic pathologist, served as La Plata County coroner from 2003-12. She now lives in Florida and Maryland. Reach her at firstname.lastname@example.org.