Wearside Jack: I deserve to go to jail for 'evil' Ripper hoax

The Kayll Road library in Sunderland had many members in the mid-1970s, but few more unusual than the avid reader in his early twenties who had a special interest in Jack the Ripper.

Despite an above-average school record, John Samuel Humble's career had never progressed beyond a bricklaying apprenticeship. But the library's crime shelves absorbed him - and no book more than Jack the Ripper, a green-covered hardback which he borrowed in 1974 and took a year to read while copying out sections of the Ripper's 1888 letter, which taunted the Metropolitan Police.

Humble's obsessions would lead him to undertake one of the most notorious hoaxes in criminal history, by sending police three taunting letters and a tape of his own in which he professed to be the 1970s Yorkshire Ripper. The letters sidetracked the entire inquiry and even made the killer, Peter Sutcliffe, feel "safe" as he killed a further three women.

But after evading justice for 28 years, Humble, 50, admitted conspiring to pervert the course of justice at Leeds Crown Court yesterday, after DNA advances had proved that he licked a small area of gummed seal on the envelope of his third note, sent in 1979.

Under interview after his arrest in October 2005, Humble said: "[The Ripper case] was getting on my nerves. It was on the bloody telly all the time. I shouldn't have done it. I know that - because it's evil. I do deserve [to go to] jail."

Humble's letters were sent by someone who had "amassed an encyclopaedic knowledge of the [Yorkshire] Ripper and his movements [and] intended to throw police off the scent," said Paul Worsley QC, who revealed that Sutcliffe had said after his arrest: "While ever that was going on I felt safe. I'm not a Geordie. I was born at Shipley [west Yorkshire]."

Humble made his two-minute tape recording while sitting at the kitchen table with a recorder belonging to his brother, who was away in the Army. The kitchen was in a mess: custard powder was found on the tape. After his 257-word message, Humble finished the tape with a short burst from Andrew Gold's 1977 song "Thank You For Being A Friend". He dispatched it in June 1979.

In part, he was motivated by a hatred for police. In 1975, aged 19, he was convicted of actual bodily harm for kicking an off-duty policeman in the head at Sunderland's Locarno ballroom, and sentenced to three months at a young offenders institution. Two years earlier, he was convicted of burglary and theft.

Assistant Chief Constable George Oldfield, leading the inquiry, played the tape at a press conference, and, guided by dialect specialists, sent officers to the Sunderland district of Castletown. Humble's neighbour, Ernie Watson, was a suspect. But officers did not knock at 15 Halstead Square, where they would have found Humble living with his widowed mother, and his brother and sister, because it was decided that the search should be confined to houses on the opposite side of the river Wear.

In September 1979, Humble had tried to halt the escalating "Wearside Jack" investigation. At 5pm on 14 September 1979, the day after the publication of a confidential police Special Notice that authorised all suspects without a North-east accent to be eliminated from the Ripper inquiry, he rang an incident room in Sunderland, where he told a young constable, Keith Mount, that the tape was a hoax. "Tell him [Oldfield] it's a fake," Humble said. PC Mount was convinced, but a Home Office lab ruled that the recorded voice did not match that on the tape.

Oldfield was mistakenly convinced that several details in Humble's letters, including a reference to the murder of a woman, Joan Harrison, in Preston, Lancashire, in 1975, could have been known only to the Ripper. He rejected the concerns of a Sunderland officer, Detective Inspector David Zackrisson, whose investigations revealed that sections of the letters were lifted from the one apparently sent to the Met by Jack the Ripper in 1888. DI Zackrissen was also puzzled by the letter-writer's failure to mention the eighth Ripper victim, Yvonne Pearson, whose body lay undiscovered under a sofa in Bradford for two months during the period of the hoax.

The hoax remained a mystery until Detective Chief Superintendent Chris Gregg, who worked on some of the Ripper murders as a young officer, established the West Yorkshire force's Homicide and Major Enquiry Team in 2004 and decided to include it in a re-examination of "cold" cases. The letters were nowhere to be found, but a plea for them elicited the vital envelope. The gum was analysed using a technique which needs only a few cells to elicit a profile. It recorded a match with Humble, who had been arrested for being drunk and disorderly in Sunderland in 2001 and had been made to provide a DNA sample

Humble is due to be sentenced today.

On the trail of the hoaxer

* Summer 1974 John Humble develops interest in Whitechapel Ripper at his local library

* 30 Oct 1975 Peter Sutcliffe, the Yorkshire Ripper, claims his first victim - Wilma McCann, 28

* March 1978 Humble sends letters to Daily Mirror and ACC George Oldfield, both postmarked Sunderland. Ripper has already killed eight times

* March 1979 Third hoax letter arrives, to Oldfield. Saliva on envelope reveals rare B secretor blood group - the same as a man who had sex with a suspected Ripper victim, Joan Harrison, before her death

* June 1979 Tape arrives with words: "I'm Jack, I see you are having no luck catching me."

* June 1979 Peter Sutcliffe interviewed and released (for fifth time)

* 14 Sept 1979 Humble tries to call police off with anonymous call saying it's a hoax; Oldfield doesn't believe him

* Aug 1980 Sutcliffe murders Marguerite Walls, 47

* Nov 1980 Sutcliffe murders Jacqueline Hill, 20

* Jan 1981 Sutcliffe isarrested by two police officers in Sheffield while with a prostitute. He confesses to Ripper murders

* 10 Sept 2001 Humble cautioned for drunk and disorderly offence and provides DNA swab

* March 2005 Police team reopens hoaxer inquiry

* October 2005 Humble is arrested at his home