An FIR in this connection was lodged after the receipt of girl's preliminary medical report, they said.
The incident happened on Friday, police said adding the girl was a student of a local college.
The girl and her alleged rapist had studied in the same school till the Higher Secondary, and, thereafter, they used to meet each other, police said.
Her boy friend kidnapped her, took her to Batala and allegedly raped her, they said.
In a complaint to police, the girl said after raping her, her boy friend brought her back to Amritsar and told her not to mention anything about the incident.
The alleged rapist was still at large.