Peter William Sutcliffe 2 June — 13 November , also known as Peter Coonan , was an English serial killer who was convicted of murdering thirteen women and attempting to murder seven others between and He was sentenced to twenty concurrent sentences of life imprisonment , which were converted to a whole life order in Two of Sutcliffe's murders took place in Manchester ; all the others were in West Yorkshire.
Criminal psychologist David Holmes characterised Sutcliffe as being an "extremely callous, sexually sadistic serial killer. Sutcliffe initially attacked women and girls in residential areas, but appears to have shifted his focus to red-light districts because he was attracted by the vulnerability of prostitutes and the perceived ambivalent attitude of police to prostitutes' safety.
Sutcliffe confessed to being the perpetrator, saying that the voice of God had sent him on a mission to kill prostitutes. At his trial he pleaded not guilty to murder on grounds of diminished responsibility , but he was convicted of murder on a majority verdict.
Following his conviction, Sutcliffe began using his mother's maiden name of Coonan. The search for Sutcliffe was one of the largest and most expensive manhunts in British history. West Yorkshire Police faced heavy and sustained criticism for their failure to catch him despite having interviewed him nine times in the course of their five-year investigation.
Owing to the sensational nature of the case, the police handled an exceptional amount of information, some of it misleading including hoax correspondence purporting to be from the "Ripper". Following Sutcliffe's conviction, the government ordered a review of the investigation, conducted by the Inspector of Constabulary Lawrence Byford , known as the "Byford Report". The findings were made fully public in , and confirmed the validity of the criticism of the force.
