Police in the Isle of Man say three fights which broke out at the weekend are connected.
The fights happened around the swing bridge on West Quay in Ramsey, between 1900 BST and 2100 BST on Sunday.
The Isle of Man Constabulary said one man was arrested at the scene but anyone who witnessed the incidents is being urged to get in touch.
The force said it was a shame so many visitors to the island for the TT races witnessed the fights.
Pc Creer, from the northern neighbourhood policing team, said: "This kind of disorder will not be tolerated in Ramsey and it is a shame that the large number of TT visitors that were in the area had to be exposed to this kind of behaviour."