"Nagendra Oraon, Amrit Oraon, Martik Oraon and Hiralal Oraon have been arrested," Superintendent of Police Michael S Raj told reporters here.
He, however, did not identify the name of the alleged rapist.
The four accused, the SP said, were among the gang of dacoits who had allegedly indulged in looting of vehicles in the wee hours of August 22 on National Highway 75 near Jagaldaga in Latehar district.
The accused belong to Jogiha village under Latehar police station, he said.
According to the FIR, she was taking the body of her brother-in-law for cremation when the incident happened.