A 21-year-old man was arrested from Palam village on Monday for allegedly creating a fake Facebook profile and posting "vulgar and abusive" comments against his aunt and her daughter, police said.
The complainant alleged that the accused also posted her photographs and that of her daughter on Facebook.
She claimed that her daughter's engagement broke off after the accused "defamed and maligned her reputation" on the social media platform.
Based on the complaint, police registered a case under relevant sections of the IT Act and the Indian Penal Code, and arrested the accused.
They said the matter relates to a property dispute between the aunt and the nephew, and the accused wanted to exact revenge.