Prasad, who retired on January 31 as Deputy Inspector General of Police (CID), was welcomed by party president and former deputy chief minister Sudesh Mahto here.
"I would like to serve the down trodden and strive to uplift rights of women. The experience in the police system will help me understand expectations of the people," Prasad said.
He became the fifth ex-IPS officer to join politics in recent years after Ajoy Kumar and Amitabh Choudhary (both Jharkhand Vikas Morcha-Prajatantric), V D Ram (BJP), Arun Oraon (BJP) and Rameshwar Oraon (Congress).