The police on Friday night recovered dozens of cow carcasses from a truck parked on a hill on the outskirts of Manesar, some 17km from Gurgaon.
When members of Gau Raksha Dal in Gurgaon got information about the truck with carcasses, they reached the spot and informed the police about the incident.
There were about 23 carcasses in the truck that had no occupants, said Jagdish Prasad, SHO Manesar police station.
Eyewitnesses, however, claimed there were more than 40 carcasses.
Police suspect a link with the Hingonia cow shed in Jaipur where a large number of cows died this week. Prasad said a probe was on.