"Two callers, who are TMC activists, threatened me with dire consequences over phone last Tuesday if I joined the BJP," Ratan Chakraborty, former chairman of TMC's Tripura unit, said.
He told reporters that he had filed an FIR with the East Agartala police station on Tuesday itself.
Officiating officer in charge of East Agartala police station Sukanta Sen Chowdhury told Chakraborty that the police had traced the callers and asked for permission from a magistrate to arrest them.