S Inbarasan was arrested based on a complaint by K Sankar of Sathanur village in the district that the four had abused him and his son using their caste name and also assaulted them.
A case had been registered under various IPC sections, including 294 (B) (obscene acts and song), 352 (criminal assault), and under the Scheduled Caste and Scheduled Tribes (Prevention of Atrocities) Act against the four.
After the boy informed his father, the latter had questioned the four when they abused him also and assaulted, police said.