They first locked the brother's rest room door and then entered the girl's rest room and sexually assaulted her, the police said.
As she screamed for help, nearby people came to her rescue and thrashed the jawans and handed four of them to police. One of them fled away.
The arrested jawans were Mandip Singh, PC Joshi, Bishnu Bahadur Rana and Arinder Singh.
Today the fifth jawan Kamal Bahadur Chetri who had fled was handed over by the army authorities to the police station, the police said.
All the five were produced in court which sent them to judicial custody.