A man allegedly racially abused a young woman at a shop in Kirton near Boston and threatened to damage the store.
The incident happened at around 5.45pm on Sunday, July 26 at the Costcutter shop on Boston Road in Kirton after the man was asked to wear a face mask, which is now compulsory in stores.
The man then got into a vehicle as a passenger, before opening the door and shouting more racial abuse. He also threatened to damage the shop.
Lincolnshire Police published an image of a man they wish to identify on July 28, who they believe could help with the investigation.
They did not specify whether the man is a suspect or a witness.
Anyone with information should contact police on 101 quoting incident 371 of July 26.