Jha had surrendered at Boileau Ganj police station of Shimla late last night, Superintendent of Police Chander Shekhar said.
Prashant was handed over to a Bihar police team headed by a sub-inspector and taken to Patna, where a case of rape had been registered against him, he said.
Earlier in the day, Jha was produced before a local court which allowed Bihar police his five-day transit remand to take him to Patna for further investigation in the case.
A minor girl was allegedly gang-raped in Patna by five school students on June 14, and CDs and MMS of the act were circulated, according to an FIR lodged by Bihar Women's Commission.
"For past few days, Jha aged about 18 years was staying with his uncle at Shoghi near Shimla," Shekhar said.
Rishabh and Arman, the two other accused in the case, have already been arrested in Bihar.
Jha, a student of Class XI in a Patna school, told police that he had come to Himachal from Delhi (where he attended coaching classes for engineering examination) to inquire about the admissions at an IT University in Waknaghat.
Police said Jha had confessed that he along with three others had sexually assaulted the minor girl on June 14 in a flat at Rajvanshi Nagar in Patna.
