Tod einer Schülerin (2010)

Alex Berger is a teacher at a secondary school. During a school trip to a lake, he has a sexual encounter with Katja Weiss, an 18-year-old student who had already been sending him admiring emails and video messages. The next day, the young woman is found dead on the shore. Many clues point to a sex crime, including the fact that a student was raped in the area several months earlier. The police investigators now suspect a serial offender. When the investigation fails to produce quick results, the public demands mass testing of all the men in the area using saliva samples. In the meantime, Berger confesses to his wife that he had an affair with the student, but denies killing her. As the date for the initially voluntary submission of saliva samples draws nearer, the teacher refuses to take part. He fears that traces of semen found on the victim’s body could make the affair public. The situation escalates when the murderer of the girl who was assaulted several months earlier is caught; however, he has a solid alibi for Katja Weiss’s murder. Berger, meanwhile, comes increasingly under the investigators’ scrutiny, as his statements about the school trip also seem implausible. Berger discovers that his 19-year-old son Benedict was also interested in Katja Weiss. Benedict eventually admits to his father that he killed Katja Weiss. Apparently, he saw his father with Katja during the trip. After his father left the area, Benedict got into an argument with the student and struck her dead with a stone. Berger then goes to the police station to confess to the crime and spare his son the legal consequences. However, Benedict also arrives at the police station during the interrogation, and his guilt is established after he confesses.