Police in Germany asked roughly 900 men on Saturday to come forward and have their DNA tested to help solve the gruesome murder of an 11-year-old girl who was killed 23 years ago.
Claudia Ruf was kidnapped in May 1996 while walking her neighbor's dog in the western city of Grevenbroich -- a case that shocked the country at the time.
Her body was found two days later in Euskirchen, 43 miles south of Grevenbroich, having been strangled, covered in gas and partially burned, according to the BBC.
No one has been charged with her death.
Investigators recently initiated the mass DNA analysis on hundreds of men in the area, with the first wave of testing beginning on Saturday, according to the BBC.
The 900 men selected for the test were between 14 and 70 years old at the time of Ruf's death and received invitations for a saliva swab test at a local primary school to have their DNA identified, the outlet reported.
DNA traces of the murderer were allegedly found on the body of Ruf, investigators hope the mass testing will lead them to the person who committed the crime. Police said that not all 900 men are suspects.
"After more than 23 years, there's a big possibility to solve the sad fate of my daughter," Claudia's father, Friedhelm Ruf, told The Associated Press. "The perpetrator has been able for too long to hide behind all of us."
Police told the Bild newspaper they've received dozens of tips to help solve the murder thanks to a renewed interest in the case, and men over the age of 14 are invited to take part in the testing.
The Rheinische Post reported that at 10 a.m. Saturday morning, the first men were already lining up outside the elementary school to get tested.
One of those men, 46-year-old Stefan Oberlies explained to Bild why he was taking part in the mass testing.
"Hopefully the culprit will be found. Of course, I have read a lot about the bad case," Oberlies told the outlet.
The new push comes after investigators in 2010 unsuccessfully tested some 350 men’s DNA in the area. They say that since those tests in 2010, they have found new hints that could help them find the murderer by checking the 900 men.
Police did not say if any of the 350 men previously tested were part of the group of 900 that they hoped to reach now.
For months, investigators asked the public for help in finding Ruf's murderer. Posters of the girl were put up on busses and trains and police distributed flyers. Over a year after her killing, the case was shown on public TV, again asking the public to come forward with tips. A reward was offered and Ruf’s case was the first in the western state of North Rhine-Westphalia to get its own homepage at the time.
The analysis of the samples will take roughly four to eight weeks, according to the BBC.
The Associated Press contributed to the report