Gulshana, a resident of Reshinad-Kremshore village of Khan Sahib, was found dead on June 3 at an isolated place in her village, two days after she went missing, a police spokesman said.
Strangulation marks around her neck prompted police to lodge a murder case and start a probe, he said.
"During the investigation, it came to light that the girl was engaged by her parents six months ago to a youth living in Gogo village of Budgam. However, the girl had an affair with a boy of her village, Javid Ahmad Bhat," he said.
Bhat confessed to killing the girl, he said.
"Bhat confessed that upon refusal of the girl to marry him and continue with the will of her parents, he got infuriated and in order to take revenge he called her to a place in the village, strangulated her to death with her scarf on the spot and left the body there," the spokesman said.