Male students and staff at a French school on Monday began providing police with DNA samples in an unprecedented operation aimed at discovering who raped a 16-year-old female pupil on the premises.
The procedure has raised concerns over rights violations after the prosecutor handling the case said anyone refusing to submit a sample would be considered a potential suspect.
By the end of the day, 251 of the 527 boys or men who have been asked to participate in the operation had provided samples at Fenelon-Notre Dame, a private Catholic high school in the port city of La Rochelle, on France's Atlantic coast.
"Nobody has objected and the samples have been taken in a calm and orderly fashion," local prosecutor Isabelle Pagenelle told reporters, defending her decision to order the tests.
"To say this is a first, does not automatically mean it is not a legitimate operation."
It was expected to take until Wednesday for all the required samples to be collected from a total of 475 male students, 31 teachers and 21 other staff known to have been on site at the time of the attack.
The girl was raped in a toilet at the school on September 30. The lights in the toilet had been turned off and the girl has not been able to identify her attacker.
A trace of male DNA taken from her clothing will be compared with the samples taken this week.
"We have nothing to go on except the DNA," said Pagenelle. "The choice was simple -- I either had to close the case or do what I have done."
She added: "There is a very strong probability that the person who did this was someone within the school who knew the building."
Each individual asked to provide a sample had to agree to the process and parental consent was also required for the minors involved.
The samples were being taken by saliva swabs under the tongue. They were to be sent to laboratories in Lyon and Nantes and the testing process is expected to take several months to complete.
Authorities said samples that do not match the DNA found on the victim will be destroyed.
- Refusing DNA test 'a right' -
Pagenelle had raised eyebrows ahead of the testing by announcing that anyone who refused to provide a sample "will become potential suspects who could be taken into custody".
"Refusing to give a DNA sample when not in custody is a right," prominent defence lawyer Joseph Cohen-Sabban told newspaper Le Figaro.
"It's ludicrous! They want to decide on taking someone into custody based on that person exercising their rights," he said. "Then, once in custody, it's against the law to refuse to give a DNA sample.... This is a truly unacceptable abuse of process."
Many of the students said they had no problem providing samples if it could help track down the rapist.
"Everyone is participating without too much trouble because we stand with the girl who was raped and want to find whoever was responsible," said 17-year-old student Lucas.
Concerned about their security, some questioned why authorities waited to move ahead with the tests.
"I don't know why it took so long, it's not normal. It's been seven months that this rapist may be in the school," said 16-year-old Margaux.