William Opia, a suspect linked to the gruesome killing of Rita Waeni, told police officers that he had bought a sharp hatchet found in his house, for self-defense.
Former Directorate of Criminal Investigations boss George Kinoti is credited with the formation of the special Criminal Research and Intelligence Bureau.
Police in Kenya have recovered a head believed to be that of a 20-year-old student who was murdered and dismembered in the capital, Nairobi, earlier this month.