Three motorcycle-borne men shot dead a former sarpanch of the Pahari village in Banmer town in the district.
The incident took place yesterday.
The assailants fled from the spot with 306 bore rifle of Bhura Singh Gurjar, the victim, police said.
It is suspected to be a case of revenge killing. Gujrar's family told police that killers belonged to the dacoit Kalli Gurjar's gang.
Police have registered a case against 12 members of the gang and started the investigations.
Kali Gurjar himself is in jail for the last six months after he surrendered before the police.
Sources said that Bhura Singh was on his way to Banmor police station to deposit his weapon after the the model code of conduct came into force, when he was attacked at a medical store where he had stopped for a cup of tea.
The killing created a tension in the village and the cremation took place amid police security.