Detectives believe they are closer to snaring a serial flasher who has repeatedly exposed himself to youngsters on a park.
Police received numerous reports a naked man had been seen approaching school children in a number of locations, including Hurst Grange Park, in Cop Lane, Penwortham, between June and September last year.
After an extensive search involving forces in other parts of the country, police now believe he may have been offending since the late 1990s.
Many of the offences involved a man exposing to school children and on each occasion the man was said to be wearing a piece of clothing around his face but his face could be seen.
Det Con Richard Horton, said: “A recent breakthrough in our investigation has revealed that our offender may have been active in the Penwortham area since the late 1990s.
“We also believe that our suspect may have visited or lived in the High Wycombe area during 2005 to 2006.
“Thankfully, we haven’t had any further reported incidents since September 2011 but this is an on-going enquiry and I am determined to bring this man to justice.
“I am asking for the help of all local people to identify him and bring his activities to an end.
“I would continue to ask pupils and parents to be vigilant and to report anything suspicious.
“If anybody has any information, no matter how trivial it seems, please contact me at Leyland police station using the new 101 number or if you would prefer to stay anonymous on the Crimestoppers number 0800 555 111.”
Among the reported incidents was September 8 and 9 last year when youngsters on a bus saw a naked man in a wooded area on Leyland Road.
Police have revealed details of a blue T-shirt and swimming style shorts which were left behind by the flasher in Hurst Grange Park.