Sujan Singh, a 32-year-old resident of Sidhrawali village here along the Delhi-Jaipur-Mumbai national highway, was shot dead on the night of February 12-13.
A case was registered at the Bilaspur police station and investigation was handed over to Gurgaon police crime branch.
Four people, including the deceased man's brother Ajit Singh, have been arrested for the murder.
"Ajit offered Rs.50 lakh to Vinod Kumar alias Murli of Sidhrawali village to kill his brother," crime branch officer Anil Kumar told IANS.
Murli further sub-contracted the killing to Vinod Singh alias Kalu and Pintu, residents of Bhora Khurd village, and promised them Rs.5 lakh each.
Police said the deceased man and his grandmother had sold agricultural land in Rajasthan at Rs.2 crore.
The money was deposited in the grandmother's account, and she gave power of attorney to the elder grandson. The joint family was also planning to sell another two acres of land.
Ajit, who lived in the joint family, however, wanted control of his grandmother's bank account and hatched the conspiracy.
On the day of the killing, Ajit left the family at a marriage function in the village, and went to inform the killers.
Kalu and Pintu reached the spot on a bike and shot dead Sujan Singh while he was walking home. Ajit had already provided nearly Rs.1.5 lakh to the killers. Police said all the accused will be presented before a court here on Monday. (IANS)