Stephan Harbort travels through German prisons to meet the serial killers behind the bars. In this case, he meets Ulrich Schmidt who target women. To his credit, five murders, three attempts and countless rapes and assaults. The second case is a serial killer woman, Berlin nurse Irene Becker, accused of killing five patients with drugs. This interview is a rarity because the majority of serial killers are men. Stéphane Bourgoin decrypts the personality of Irene Becker.