The BBC's Bonn correspondent Caroline Wyatt: "Body found in woods" (0'58")

Police say saliva tests were carried out on about 15,000 men living in and around Cloppenburg, north west Germany.

The mass test was undertaken after public outrage following several murders of teenage girls.

The arrested man, a father-of-three, voluntarily took part in the mass test.

He is being held in connection with the sexual assault and murder of 11-year-old Christina Nytsch.

The testing involved 15,000 people

She was sexually abused and strangled while on her way home from a swimming pool on March 16.

Hans-Juergen Thurau, head of the police investigation, said: "We were able to track down the killer with the help of the genetic fingerprint left behind at the crime scene."

Police say the man, an unemployed mechanic, has also admitted to a similar rape in 1996.

The arrested man is 30-year-old who police say served three years in jail for a previous sex abuse conviction.

He was considered a suspect during the investigation's early stages but police did not pursue the lead because he voluntarily took part in the testing programme.

A special police commission called on all 15,000 men between the ages of 18 and 30 in Cloppenburg and 35 surrounding villages to come forward for the tests.

Initially 12,000 volunteered drawing criticism that it had been a wasted effort because so many men had not taken part.

Following intensive canvassing by police another 2,700 came forward leaving just 300 men untested.