PC Jon Evans is appealing for witnesses to an altercation on a local Stagecoach number seven bus.
The incident happened on the number seven Stagecoach bus from Boston to Skegness on Thursday, September 18.
At approximately 4.30pm, when the bus had reached Friskney, a male passenger was asked to leave the bus.
As he did so, he was involved in an altercation with another male.
Anyone with information should contact PC Evans by dialling 101 and quoting incident number 299 of September 18.
You can report crimes anonymously by contacting Crimestoppers on 0800 555 111.