A man exposed himself outside a property in Rosehill Road at around 2.50am on Tuesday (May 10).
Police said the incident was being linked to several others which happened in Burnley, Padiham and Pendle.
DC Lee Walker, of East CID, said: “These incidents are clearly very distressing for the victims.
“We are doing all we can to identify the individual responsible and we have a dedicated team of officers assigned to this case.”
The first incident happened outside a property in Pasturegate at around 5.05pm on August 17, 2021.
The second happened outside a property in Hardy Avenue, Nelson, at 11.10pm on December 31.
The third happened outside a property in Padiham Road, Burnley, at 7.15am on January 27.
The fourth happened outside a property in Manchester Road, Burnley, at 6.03am on February 2.
The fifth happened outside a property in Pasturegate, Burnley, at 5.17am on April 24.
The suspect is described as a white, in his 20’s, short and of a stocky build.
Two men previously arrested as part of police enquiries have been released with no action.
Detectives said enquiries were ongoing to identify the individual responsible.
Residents were urged to check their CCTV, dashcam or doorbell footage to see if they captured anybody acting suspiciously in the areas of the offences at the time.
“I appreciate some time has passed since some of the incidents have happened, but I would ask anybody with information which could assist our enquiries to contact the police as soon as possible,” DC Lee Walker added.
“I would also ask people to check any footage they may have covering the areas the offences have taken place at to see if they have captured anything which could assist our investigation.
“Finally, I want to appeal directly to the person who is committing these crimes to search his conscience, do the decent thing and hand himself in.”
Anyone with information or footage can email [email protected] or call 101, quoting log number 0796 of May 10, 2022.