Police are looking for information after a man in the city indecently exposed himself on January 27.
The incident happened around 7.40am outside Sippers pub on Melville Street, where the man walked towards the the city centre with his penis exposed.
The offender is described as a slim white male in his 50s, with short brown hair. He was wearing light blue jeans and a grey top.
If anyone saw the incident or has any information on the male, call Lincolnshire Police on 0300 111 0300.