Manju, a student of Arya Samaj Inter College and a resident of Hasanpur, was kidnapped from near the college. Four men grabbed her from behind when she was deboarding an auto-rickshaw and forced her into their van, ASP Sanjay Singh said.
He said Manju left for college along with her three friends. The three girls told police that by the time they called for help, the van had disappeared.
Singh added a few days ago Manju had opposed harassment by a boy who had threatened her of consequences.
Police resorted to a lathicharge to disperse the crowd.
A kidnapping case has been lodged by the family members of the girl at the Sadar Bazaar police station.