Police travelled to the Sunderland area where they arrested a man aged 49 on suspicion of attempting to pervert the course of justice.
The letters and tape diverted police attention away from the hunt for the real killer, Peter Sutcliffe, during the inquiry almost 30 years ago. Police switched their murder hunt from Yorkshire to Sunderland during the period when the real Yorkshire Ripper murdered three more women.
Sutcliffe,who was from Bradford, was questioned a number of times during what was then the biggest manhunt in British history. He was eliminated from the inquiry by police. One of the reasons was that he did not have a Wearside accent.
The hoaxer sent the detective leading the inquiry, George Oldfield, three letters and one audio tape, which was broadcast nationally in June 1979. The chilling two-minute message on the tape, spoken in a heavy accent said to be from the Castletown area of Sunderland, started: "I'm Jack. I see you are still having no luck catching me ... 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 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."
The first letter was sent to Mr Oldfield in March 1978, saying: "You probably look for me in Sunderland, don't bother, I am not daft, just posted letter there on one of my trips. Not a bad place compared with Chapeltown and Manningham and other places. Warn whores to keep off streets cause I feel it coming on again."
The second was sent to the Daily Mirror and the third to Mr Oldfield, saying: "I wasn't kidding last time I wrote saying the whore would be older this time and maybe I'd strike in Manchester for a change, you should have took heed."
The hoax led to years of additional police work, costing more than £4m. Almost £1m was spent on a resultant publicity campaign.
The linguistics expert Stanley Ellis concluded that the voice on the tape came from a man from the former pit village of Castletown, Sunderland. Suspicion hung over this small community for another year and a half, until Sutcliffe was caught in Sheffield early in 1981, after a routine traffic inquiry.
In July, West Yorkshire Police said that the audio tape and letters from the hoaxer had been misplaced.
Mr Oldfield died in 1985. Sutcliffe, aged 59, was jailed for life in May 1981, after admitting the murders of 13 women and the attempted murders of seven others between 1978 and 1980. He is in Broadmoor Special Hospital.
"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?
"At the rate I'm going I should be in the book of records. I think it's eleven 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..."Reuse content