The class X student had gone missing in Shimla district on July 4 and her body was recovered from the nearby Halila forest two days later. The police had registered a case against unknown people.
Based on evidence gathered so far, a police team arrested Ashish Chauhan alias Ashu, 29, a resident of Sharaal village in the Mahasu area of Kotkhai, said Inspector General of Police (Southern Range) Zahur H Zaidi, who is also heading the SIT.
The SIT is in the process of collecting more evidence and more arrests are likely in the days to come, Director General of Police (DGP) Somesh Goyal said.
Such posts can attract civil and criminal liability, he said, apart from making the case more complicated. He also requested people of the state to have patience and trust in the police.
Meanwhile, protests by students, political and social organisations demanding justice for the minor girl continued in Shimla and Kotkhai.