The thirteen murders committed by the Yorkshire Ripper over a time of five years, between 1975 and 1980, kept a few cities in Yorkshire in a grip of fear. His victims were mostly - however not exclusively - prostitutes, and that association with Jack the Ripper delivered Sutcliffe's nickname.

He ran off the slums of Leeds and Bradford and picked up women there. Sutcliffe took great risks by driving his car through the streets, looking for potential victims, in order to kill them in alleys, often not more than a stone's throw away from busy streets. He was unbelievably lucky, because he was examined several times during the police investigation, which tempted the papers to headlines such as: 'the police lets the ripper go 9 times'.

In a way that would later on be compared to Ted Bundy's, this killer struck his victims, after which he sexually abused the dying women. When they had died, he mutilated the remains with a knife. His first victim was Wilma McCann, who was killed in October 1975 in Leeds, and the last victim was Jacqueline Hill, killed in November 1980, also from Leeds. Between those murders, other killings took place in Bradford, Manchester, Huddersfield and Halifax, and another four in Leeds. The police started a large-scale investigation, by which in total, 250.000 persons were interrogated, 32.000 statements were took and 5.2 million number-plates were checked, this all at the cost of £ 4 million. The police was hassled with notes and tapes that would be sent by the killer, and much valuable time was lost with false indications. For instance, extremely harmful was the sending of a tape got by the police after the eleventh murder. The tape was addressed to the chief inspector of Yorkshire, George Oldfield. The voice on the tape seemed to be a grown man's who spoke slowly and formal. There were lots of background noises. The announcement on the tape lasted about two minutes:

"I'm Jack. I notice you still haven't managed to catch me. I have great respects for you, George, but in four years of investigations, you haven't got far yet. I think your boys haven't got confidence in you anymore. The only time they were close to me was a few months ago, in Chapeltown, where you disturbed me. Then, it also was a normal cop in uniform, no detective. I warned you in March that I would strike again, but I couldn't go there. I don't know exactly when I'm going to strike again, but at all rate it'll be sometime this year, September or October maybe, or even sooner when I get the chance there are enough of them to fool. They never learn, do they, George I'll do keep going for a while. I don't see myself that soon in prison. But even if you guys come near me, I'll probably exceed myself. Well, it's been nice talking to you, George"

'Jack' encouraged Oldfield also to listen to the 'nice song' on the tape. It was a part of the record that's called 'Thank you for being a friend'. Dialect experts found out that the voice came from Wearside, and the tape was played in several pubs and clubs, in the hope that someone could recollect the voice. At one of the occasions that Sutcliffe was interrogated, they let him go because he didn't speak with a Wearside accent. After Sutcliffe was arrested and convicted, further investigation made clear who sent that misleading tape. It had been a retired police officer who hated chief inspector Oldfield and who had sent him the tape, in order to harass him.

The five years during investigation of the Yorkshire Ripper ended, January 2nd 1981, in Sheffield. A police car saw a car parked on a dark drive en the officers decided to interrogate the occupants. The man said he was called Peter Williams, but he wasn't capable to name his female companion, of which the police supposed she was a prostitute. Unsatisfied with his answers, one of the police officers asked the police headquarters to check the car's number-plate. Within a few minutes, there was an answer; it seemed that the number belonged to another car-brand. At that time, the game was over for Peter Sutcliffe, who was taken for interrogation.

Sutcliffe's trial started May 5th 1981, and he denied guilt on the ground of diminished sanity. He would be a rather introvert person, but in 1967, he already married the girl that he had been running after for seven years. They lived in Bradford, where she was a teacher and he was a truck driver. Neither his wife, neither his colleagues had any clue about Sutcliffe's violent double life, however there maybe was a small sign for what was about to come in the message he had attached to the rear window of his car: 'In this truck sits a man who, if his latent geniality gets a free hand one day, will shake the nation to her foundations; a man whose dynamic energy will overwhelm the people around him. Maybe you should let him sleep?'

Sutcliffe admitted to feel an enormous hate against prostitutes and a part of his defense was based on the belief that he had a mission of God to fulfill by clear out the world of them. He received his godly instructions when he stood on a cemetery in Bingley and looked out over the moorlands. After three weeks of hearing testimonies and evidence, the jury concluded that Sutcliffe was rather evil than insane, although he claimed to have acted on the order of 'voices'. They judged him guilty of thirteen murders and he was convicted to a life sentence. Three years later however, he got transferred to a mental institution because of his mental illness. He's a paranoid schizophrenic. And if that deviation hasn't arisen in prison, he always has been.