Aktenzeichen XY... ungelöst ("Case number XY... unsolved") is a German interactive television programme first broadcast on 20 October 1967 on ZDF. Created by Eduard Zimmermann, it aims to combat and solve crimes. The programme is currently presented by Rudi Cerne. It airs monthly, with 12 episodes in a year, on Wednesday at 8:15 PM. From March 1968 until December 2002, it was produced in cooperation with the Austrian public service broadcaster ORF and Schweizer Fernsehen, a division of the Swiss public broadcaster SRG SSR, who joined in January 1969 and left in December 2003. The programme was adapted by the BBC as Crimewatch and for the US market as America's Most Wanted. Other adaptations of the format were aired in a number of countries including Ireland, Israel, Italy, Netherlands, New Zealand, Poland and Sweden. Format The goal of the programme is to cast light on unsolved offences with the aid of viewers. Each episode contains three to five short films, each lasting about ten minutes, in which a real criminal case is reconstructed. The cases are mostly complex ones in which the criminals and chains of events are still unknown. In addition, cases are discussed in the studio in which, for example, the identities of criminals or unknown murder victims are sought with the aid of a photo. Viewers can use the telephone or internet to give information. According to a study by the programme's editorial department, about forty percent of cases shown on the programme are solved. History The creator and first presenter of the programme was Eduard Zimmermann. After the programme's 300th episode he passed the presentership onto Butz Peters, who fronted the show together with Zimmermann's daughter Sabine. Since 18 January 2002 Aktenzeichen XY has been presented by Rudi Cerne. With Aktenzeichen XY Eduard Zimmermann and ZDF succeeded in starting a TV format that had not existed worldwide until 1967. Although news reports had often shown photofits, an actual independent show of this type was unknown at this time. The idea came to Zimmermann during his work with the programme (Eng: Beware, Trap!) first broadcast in 1963, in which he warned the viewers of "Nepper, Schlepper und Bauernfänger" (Eng: Scammers, Hustlers and Conmen). The viewers frequently sent him information regarding descriptions of the fraudsters on the programme. This gave him the idea to use the medium of TV to work with the police on unsolved crimes. In