SP City Arun Kumar Singh said the girls were were identified as Laxmi (18) and Nisha (14). Their father hailed from Bulandshahr and the family was living in a rented house here in Sector 49.
The police received information about the sisters this morning following which a team reached their house. They pulled down the bodies and sent them for post-mortem, he said.
While Nisha was studying in a school, Laxmi was working with a private company.
The police detained Kulbhusan for questioning who claimed that his elder daughter was in love with a youth, Prem, and she had eloped with him ten days ago. However, she returned home a few days ago following which he had scolded her.
The official said the matter was being investigated from all possible angles, including murder and honour killing.