The suspected militants, identified as Sandan Basumatri, Naseen Basumatri, Jibal Nursey and Tomar Basumatri, and aged in their twenties, were working in a factory at Peenya Industrial area here and hiding in the city for the past one year, police said.
They would be produced before the magistrate for transit to Assam, police added.
Rajgopalnagar police have registered a case and are investigating.
Earlier, in January the city police had arrested top Bodo militant, Bikhang Basumatri, who was allegedly involved in the December violence in Assam.