British detectives are continuing to question a man in connection with the so-called "Wearside Jack" hoax letters and tape sent to the Yorkshire Ripper inquiry team.
The 49-year-old man was arrested in the Sunderland area on suspicion of attempting to pervert the course of justice. Officers from West Yorkshire Police travelled to Sunderland to arrest the man before taking him back to Leeds for questioning.
The hoax letters and tape featuring a man with a strong Wearside accent purporting to have carried out the Ripper murders and taunting officers, is widely believed to have diverted resources from the investigation which eventually led to the capture and conviction of Peter Sutcliffe.
A police spokesman said the arrest "relates to the hoax letters and tape that was sent to police during the Yorkshire Ripper murder investigation".
Yorkshire Ripper Peter Sutcliffe, from Bradford, now 59, was jailed for life in 1981 for the murder of 13 women.
In the late 1970s and 1980 his murders brought terror across the north of England and there was huge pressure on the West Yorkshire Police murder team, headed by Assistant Chief Constable George Oldfield.
But the inquiry - the biggest manhunt Britain had ever seen - was led down a blind alley by the three letters and a tape sent to the investigation team by a man dubbed Wearside Jack due to his strong Sunderland accept.
The first letter was sent to Mr Oldfield in March 1978. The second was sent to the Daily Mirror and the third to Mr Oldfield again.
The tape was also sent to the detective and taunted him and his officers.
Mr Oldfield died in 1985. Sutcliffe is currently in Broadmoor Special Hospital.
PA