The police traced the identity of Nitin after finding his address through the chassis number of the badly burnt car.
The car was registered on a Rohtak address and from there the police found his current residence of Gurgaon.
When the police reached Pratik Apartments at Sector 120 in Gurgaon, they found bodies of his wife and five-year-old daughter.
Prima facie, Nitin might have killed them and later committed suicide, he said, adding the murder by a third person is not ruled out and a probe is on.
Nitin was working at a private company in Greater Noida.