Peter Coonan (born Peter William Sutcliffe; 2 June 1946) is an English serial killer who was dubbed the "Yorkshire Ripper" by the press. In 1981, Sutcliffe was convicted of murdering thirteen women and attempting to murder seven others.

Sutcliffe had regularly used the services of prostitutes in Leeds and Bradford. His outbreak of violence towards them seems to have occurred because he was swindled out of money by a prostitute and her pimp. When interviewed by authorities, however, he claimed that the voice of God had sent him on a mission to kill prostitutes. Sutcliffe carried out his murder spree over five years, during which time the public were especially shocked by the murders of women who were not prostitutes. After his arrest for driving with false number plates in January 1981, the police questioned him about the killings and he confessed that he was the perpetrator.

At his trial in 1981, he pleaded not guilty to murder on grounds of diminished responsibility after a diagnosis of paranoid schizophrenia but his defence was rejected by a majority of the jury. He is serving 20 concurrent sentences of life imprisonment. Following his conviction, Sutcliffe began using his mother's maiden name and became known as Peter William Coonan.

West Yorkshire Police were criticised for the time taken in apprehending Sutcliffe despite interviewing him nine times during the murder hunt. Because of the sensational nature of the case, the police handled an exceptional amount of information, some of it misleading, including a hoax recorded message and letters purporting to be from the "Ripper" but the 2006 Byford Report of the official enquiry confirmed the validity of the criticism.

The High Court dismissed an appeal by Sutcliffe in 2010, confirming that he would serve a whole life order and never be released from custody.[1] On 11 August 2016, it was ruled that Sutcliffe is mentally fit to be returned to prison. On 24 August 2016 he was moved to HM Prison Frankland in Durham.