He said the party had authorised Chief Minister Raghubar Das and state party chief Laxman Gilua to take decision on the candidate and Das took the opinion of party workers in Dumka on March 16 and then Murmu's candidature was announced.
His name would be sent for approval to the party's national president Amit Shah, Prabhakar said.
The bypoll has been necessitated following the death of JMM MLA Anil Murmu on January 17.
The bypoll will be held on April 9.