text:  Police say he's confessed to the killings. Speaking to the press, the head of the criminal investigation, Mohamed Amin, described the suspect as a psychopathic serial killer. We're dealing with a vampire, he said. It's a really grim story, this. The discovery of dismembered bodies at a local dump site triggered the investigation. The BBC's Africa security correspondent, Ian Wafula, has been giving me more details.