New Delhi, March 21 (IANS): Four persons were arrested on Tuesday for beating a 28-year-old mentally challenged youth to death here on a suspicion that he committed a theft at a haystack godown, the Delhi Police said.

Deputy Commissioner of Police Milind Dumbre said all the four persons were apprehended till Monday night and were formally arrested later when they divulged the murder of Shankar Ram, a resident of Jahangirpuri in west Delhi.

The four -- Andip, Subhash, Anoop and Harender-- all mainly known by their first names, were arrested under sections of the Indian Penal Code relating to murder and causing disappearance of evidence.

The police officer said the four accused beat up the youth badly with wooden sticks on Sunday night after tying him with the coupling of a tractor-trailer on the suspicion that he committed theft in a haystack godown.

"One more person accused of the murder will be arrested soon," the officer said.

Dumbre said that the victim was "mentally challenged" and had been receiving medical treatment for a few years.

The police learnt about the lynching after a villager made a call to the Police Control Room around 7.15 a.m. on Monday about a body lying in a nearby field. 

During interrogation, the police got to know that the victim was attacked by a group of persons in west Delhi's Swaroop Nagar area on Sunday night, just a few metres away from where he was found dead. 

Investigators said they arrested the four men after one of the eyewitnesses of the incident, security guard Jai Kumar, claimed he had seen a group of persons thrashing Shankar Ram while returning home. The witness said some people tried to rescue Shankar Ram, but the attackers threatened them. 

"The accused dumped the victim at the secluded field after he lost his consciousness," an investigator added.