Murderer accidentally kills himself while performing sex act in jail A sadomasochistic serial murderer accidentally killed himself in his prison cell after performing a sex act that involved electricity and his genitals. Police in Germany said Egidius Schiffer, 62, accidentally died while performing the 'autoerotic act' and that there was no reason to suspect foul play or suicide. Schiffer was known as the 'Aachen Strangler' after he was jailed for murdering five female hitchhikers between 1983 and 1990. Candida Tunkel, a spokeswoman for Bochum prison in northwest Germany, said a cable from his bedside lamp was used during the sex act, The Times reported. A post-mortem revealed the cause of death was heart failure caused by a surge of electricity through his chest. Schiffer murdered his victims - aged between 15 and 31 - after picking them up in his car as they travelled home from night clubs. He tied them up and strangled them with rope before burying their bodies in woodland. He raped three of them, the MailOnline reported. Police caught him 18 years after his last murder when he was arrested in 2007 for stealing scrap metal. DNA evidence linked him to the murders. He was sentenced to life imprisonment in 2008, Bild reported. Schiffer - who was married and has a son - confessed but later withdrew his statement. He claimed that he had only wanted to experience the punishment of being in custody because, as a sadomasochist, it excited him.