John Humble, 50, has been jailed for eight years after pleading guilty to four charges of perverting the course of justice over the Yorkshire Ripper killings.
His admission brought an end to the "Wearside Jack" mystery - the nickname given to the caller behind the infamous bogus tapes which claimed to have been made by the killer.
Humble, a former labourer from Sunderland, kept his secret for 30 years before DNA implicated him.
BBC News recalls the background to the case and the impact the hoax had on police investigators.
For the man leading the hunt for the Yorkshire Ripper it was to be his biggest gamble.
Huge swathes of the north of England were gripped by fear after a series of murders which had claimed the lives of 10 women by the summer of 1979.
But Assistant Chief Constable George Oldfield, who was in charge of West Yorkshire Police's Ripper Squad, believed he possessed what could prove to be a priceless lead.
In June 1979, he had been sent a tape recording by a man claiming to be "Jack" who had carried out the grisly murders.
The cassette followed three letters sent over the previous 12 months by what appeared to be the same man claiming responsibility for the killings.
'Not a detective'
The voice on the tape taunted Mr Oldfield, who was coming under tremendous pressure to catch the Ripper, and suggested his police colleagues were letting him down and that the killer would strike again.
George Oldfield: Put his faith in the tape
It said: "I'm Jack. I see you are still having no luck catching me. I have the greatest respect for you George, but Lord! You are no nearer catching me now than four years ago when I started. I reckon your boys are letting you down, George. They can't be much good can they?
"The only time they came near catching me was a few months back in Chapeltown when I was disturbed. Even then it was a uniformed copper not a detective.
"I warned you in March that I'd strike again. Sorry it wasn't Bradford. I did promise you that but I couldn't get there. I'm not quite sure when I will strike again but it will definitely be sometime this year, maybe September, October, even sooner if I get the chance. I am not sure where, maybe Manchester,
"I like it there, there's plenty of them knocking about. They never learn do they George? I bet you've warned them, but they never listen.
"At the rate I'm going I should be in the book of records. I think it's eleven (sic) up to now isn't it?
"Well, I'll keep on going for quite a while yet. I can't see meself being nicked just yet. Even if you do get near I'll probably top myself first. Well, it's been nice chatting to you George. Yours, Jack the Ripper.
"No good looking for fingerprints. You should know by now it's as clean as a whistle. See you soon. Bye.
"Hope you like the catchy tune at the end. Ha Ha."
The recording finished with a 22-second clip from the song Thank You For Being A Friend, by Andrew Gold.
However, together with the mocking tone, "Jack" also appeared to be giving detectives a vital clue - he spoke with a distinctive Wearside accent.
With politicians and the media clamouring for a breakthrough in the case, Mr Oldfield took the decision to go public with the letters and tapes.
As well as organising a huge publicity campaign, police also consulted with voice analysts who insisted the accent was from the Castletown area of Sunderland.
Forensic experts have searched Humble's house in Sunderland
A total of 40,000 men were quizzed in connection with the tape, but to no avail - because the real culprit was Peter Sutcliffe from Bradford, a softly-spoken Yorkshire man.
He was interviewed about the murders only to be eliminated because he did not sound as if he was from Sunderland.
When the 33-year-old confessed to the killings 18 months later it proved the "Wearside Jack" letters and tape to be a hoax.
But, while West Yorkshire Police were chasing the scent of a Wearside suspect, the real Ripper was free to carry on his chilling campaign - murdering three more women.
Mr Oldfield never recovered from what he regarded as a humiliation. He took early retirement and died in Wakefield in 1985, at the age of 61.
Although he was never the subject of a massive manhunt in the wake of the case, the hoaxer was blamed for altering the course of the Ripper inquiry to devastating effect.
He also left police with a £1m bill for the publicity drive, which included billboard and national newspaper adverts.
Yet any efforts to catch "Wearside Jack" were officially abandoned in September 2003, with police saying they would be unable to prosecute any suspect because of the time that had elapsed.
But a review of "cold cases", using the latest DNA tests, managed to identify Humble by matching his genetic profile with a sample he had given five years ago after he was arrested for being drunk and disorderly.