The charred bodies were found bundled in the car, Jhajjar SP Rajesh Duggal said over phone.
The car was suspected to have been set on fire and someone informed the police about it.
"The bodies were charred beyond recognition. Only the skeletal remains were found. We managed to trace out the identity of the deceased from the Toyota Etios car's registration number," the SP said.
Duggal said the Issrehdia village from where the bodies were found was located on Haryana-Delhi border.
The deceased were identified as Sandeep, Manish, Sudhir and Deepak.