English police trying to solve the rape and murder of two teenage girls in the village of Narborough were the first to use mass DNA collection in 1986, sampling 5,000 men in the earliest days of genetic testing. Police found the killer, Colin Pitchfork, after he asked a friend for a substitute blood sample.
France has also used DNA dragnets, including in 1997 when police trying to solve the rape and murder of a 13-year-old British girl ordered testing for about 3,400 men and boys. In 2004, investigators trying to solve the murder of an 11-year-old boy took 2,300 samples. Neither crime was solved.
Last year, a judge in Brittany ordered DNA tests for all 800 men and boys ages 15 to 75 living in a town plagued with arson fires. The man ultimately charged, a local grocer, had been tested but was arrested only after two more fires and more investigation.
When the DNA database was created, French privacy rights advocates said they were comfortable with it because it had clear limitations, said Jean-Pierre Dubois of the French League of Human Rights. Over time, he said, those limits have blurred.
"We are very surprised that the police officers have not been able to be a bit more precise. When you make an inquiry, you have other evidence and other testimony," Dubois said. "Otherwise, you could say why only the people in the school? Why not all the inhabitants of the town or the region?"
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