Pehlu Khan was beaten to death by a group of cow vigilantes in Rajasthan's Alwar in 2017.

The Rajasthan police has sought permission from an Alwar court to investigate further the case against the two sons of Pehlu Khan, who was beaten to death by cow vigilantes two years ago for allegedly transporting the animals illegally.

The Ashok Gehlot-led Congress government in Rajasthan had faced criticism late last month after a chargesheet was filed against Khan's sons, Irshad Khan, 25, Aarif Khan, 22, and a truck operator, Khan Mohammad, in the cow smuggling case.

Mr Gehlot had then responded that the police could reinvestigate aspects of the case, filed when the BJP government was in power.

Alwar Superintendent of Police Anil Paris Deshmukh said on Tuesday that the police filed an application in the court of additional chief judicial magistrate on Saturday, seeking permission to further investigate the cow smuggling case.

"Certain aspects will be further investigated. His sons have said that they were going to sell the animals in Tapukara (in Alwar) and the truck operator claims that he had sold the vehicle to someone else before the incident had taken place," Mr Deshmukh said.

Earlier, the police had said the animals were being taken to Haryana. Also, Khan Mohammad could be cleared of the charges if it is proved that the truck did not now belong to him.

The three have been charged under the Rajasthan law against cattle smuggling. Pehlu Khan's name was dropped in the chargesheet as he has died, the police said.

Pehlu Khan and his sons were beaten up by a mob on the suspicion of cow smuggling on Aprli 1, 2017. He died at a hospital in Alwar on April 3. They were on their way to Haryana's Nuh district from Jaipur when the cow vigilantes stopped two of the vehicles on the Jaipur-Delhi national highway.

The Rajasthan police had registered a case against the people who allegedly lynched Pehlu Khan and thrashed his companions. Six men were named in the police case, which also mentioned around 200 unidentified people.

A separate case was also registered then against Pehlu Khan and others under the cattle smuggling law, which allows the transportation of cattle only after getting permission from the administration. Police had then booked 16 people for illegally transporting 36 animals in six vehicles.