BERLIN (AP) — Police in the western German city of Grevenbroich have asked about 900 men to come forward and have their DNA tested to help solve the gruesome killing of an 11-year-old girl some 23 years ago.

The girl, Claudia Ruf, was kidnapped, raped and choked to death by an anonymous murderer in 1996. Her body was found in Euskirchen, 70 kilometers (43 miles) south of Grevenbroich.

German news agency dpa reported Saturday that 900 men, who were between 14 and 70 years old at the time of Ruf’s killing, have received invitations for a saliva swab test to have their DNA identified.

Investigators already unsuccessfully tested some 350 men’s DNA in 2010. They say they now found new hints that could help them find the murderer by checking the 900 men.