Her family claimed she consumed poison but villagers alleged that she was killed over her affair with a man, they said.
Khateeja, a student of BA at RBD Girls Degree College in Bijnor, was in a relationship with Saarif (25) for the last two years.
The couple got married a few days ago in civil court against the wishes of the woman's family, the police said.
Upset over the marriage, her family killed her on Saturday night and told the people that she had committed suicide, villagers alleged.
According to the post mortem report, the woman was strangulated. Injury marks on the cheeks and chin were also found, Superintendent of Police Prabhakar Chaudhary said.
A case of murder has been registered and a probe is on in the matter, SP Chaudhary said.