Lincolnshire Police are warning people not to walk through Lincoln city centre alone at night after a man followed a woman to the door of her home before exposing himself through her window.
Officers are investigating a report that a woman was walking down Lincoln High Street on September 24 at around 10.45pm when she noticed she was being followed.
After entering her home on Shakespeare Street, she noticed the man was at her window and appeared to be masturbating.
The suspect is described as a white man around 5ft 2 inches tall, wearing a dark hoody and dark jeans.
Lincoln Community Inspector Pat Coates said: “This incident is under investigation and a number of enquiries are being carried out in relation to it.
“This type of incident is rare and we believe this is a one-off. However, we are keen to hear from anyone else if they might have experienced anything of this nature or seen a man acting suspiciously in the area. The more information we have the fuller a picture we can build.
“The lady involved in this has done exactly the right thing by quickly calling police with her concerns.
“Although we believe this is an isolated incident it is a timely opportunity to remind people, and especially lone women, to be vigilant around personal security.
“If you are a woman try to always travel in pairs during the late evening or try and take a marked and licensed taxi.
“If that’s not possible then try and plan your route ahead, use busy, well-lit streets, and avoid wearing headphones or chatting on your mobile.
“Stay alert and call police as soon as possible if you feel unsafe or want to report anything suspicious to us.”
Anyone with any information is asked to contact Lincolnshire Police on the non-emergency number 101 quoting incident 534 of September 24.
Alternatively, people can contact the independent charity Crimestoppers anonymously on 0800 555 111.