Witnesses are being sough after a fight between a group of youths and a 61-year-old man in Horncastle.
The incident took place at around 11pm on Thursday July 9 in Boston Road.
The man suffered an arm injury after being struck by a wheelie bin.
DC Becky Fowler would like to hear from any witnesses, in particular a female in a black dress who assisted the victim.
Anyone with information should contact Lincolnshire Police by dialling 101 and quoting the incident number. Report crimes anonymously by contacting Crimestoppers on 0800 555 111.