John Humble taunted detectives when he claimed to be the Ripper in three letters and an audio tape in the 1970s.
His actions made police concentrate their hunt in Sunderland, while the Ripper continued to kill in Yorkshire. It is estimated that it allowed Peter Sutcliffe to go on to kill at least three more women.
Humble’s hoax sent police on the biggest wild goose chase in British criminal history.
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All the letters were stamped with a Sunderland postmark, and officers pinpointed the accent on the tape down to the Castletown area of the city.
Humble escaped justice for decades, but his identity was discovered 25 years later when his DNA, taken after a minor offence, was matched against saliva on an envelope sent to detectives.
In March 2006 he admitted four charges of perverting the course of justice and was jailed for eight years. Judge Norman Jones told him his offences were at the upper end of seriousness when it came to perverting justice.
It is reported that after Humble was released in 2009, he was moved to South Shields, South Tyneside, and given a new identity, John Samuel Anderson. It is understood that Humble died in July.
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Sutcliffe was convicted of murdering 13 women and attempting to murder seven others in 1981.
He is currently serving life at Durham’s Frankland Prison.
When Humble was jailed for the hoax, Sutcliffe wrote to him saying ‘you have blood on your hands’.
Sutcliffe blamed Humble for the deaths of his final three victims. He wrote: "You could have saved those three women, John. You have blood on your hands.
"You could even end up in Broadmoor with me. That is where you belong."