Ripper may be responsible for more than ten other unsolved crimes.

Sir Lawrence Byford former chief inspector of constabulary put in a report in 1981 and some pages have recently been released for consideration:- between 1975 and 1981 Peter Sutcliffe was found guilty of 13 murders and 7 attempted murders and may have carried out up to 13 further attacks and been active for a longer period. Police had made mistakes with photofit evidence and had not applied enough criteria to increase research into other unsolved crimes at the time.  West Yorkshire Police said it was “continuing …to review non-recent undetected offences”.