Ranjan alleged that Maya Mandal, Sangeeta Oraon and Sita Goswami were allegedly raped and later killed at Laxmipurbhita village and Ithari villages under Dhamdaha police station recently.
Ranjan alleged that the incident occurred under "the patronage of ruling NDA leaders" in Purnia.
Ranjan accused the police of trying to cover up the incident and requested the Governor to ask the state government to order a judicial probe into the allegation.
The Congress leader alleged that cases of rape and murder had increased in Purnia district and urged Konwar to ask the state government to check recurrence of such incidents.