The incident occurred when police took V Karthick, an accused in a case, to Kenikarai police station after producing him before a magistrate for questioning in connection with a case, police said.
Constable Suresh and Kathick had an heated argument during questioning.
After Suresh allegedly lost his cool during the interrogation, he bit Karthick's body injuring him, following which he was admitted to hospital.
A case has been registered against Suresh, already facing a case in connection with pistol missing, police said.