A male victim was hit in the head and body several times in an unprovoked attack in Gainsborough last month.
An offender on a bicycle chased the victim on Beaufort Street in Gainsborough at around 11pm on August 18.
He pushed him before hitting him in the head several times and his body.
Police are trying to identify a man who may be able to help with their investigation and they have issued a CCTV image.
Anyone with information about the incident, or who recognises the man, should contact police on 101 or via email at [email protected] quoting incident number 498 of August 18.
It can also be reported through the independent charity Crimestoppers anonymously on 0800 555 111 or online here.