"Dhanu Kumar, son of Deputy Superintendent of Police (CID) Arjun Ram, and Anurag Basu alias Anurag Paswan, son of constable cum driver Mahendra Paswan, posted in Bihar's Rohtash district, were arrested in Hazaribagh town," Superintendent of Police Manoj Kaushik said.
In all, three of the four accused are sons of policemen posted at different places, he said.
Ritesh Kumar, son of Constable Umesh Sharma, posted with the India Reserved Battalion, and one Sonu Kumar were arrested on Thursday.
He said the duo was arrested near the new bus stand in the town when they were coming to Hazaribagh from Ranchi to surrender before the court of the judicial magistrate.
The four men were accused of kidnapping the girl on August 26 near her house in the town, took her by car to a bungalow on Kanhari Hill Road and raped her for three days.