In Bhubaneswar, around half-a-dozen posters warning people against supporting the proposed December 25 Orissa bandh by the RSS, VHP and BJP were found plastered on public walls. Unlike the usual Maoist posters which carry some sign of the Maoist office-bearers, the posters that were discovered in Nayapalli were unsigned and warned people against joining groups that were allegedly involved in religious violence. The posters described the RSS, VHP and Bajrang Dal as rioters.

The police have registered a case and sent the posters for forensic examination.

However, Bhubaneswar Deputy Commissioner of Police Himanshu Lal said the posters could be "pure mischief". "Prima facie it seems like that. But we are investigating it," he said.

In a separate incident, Congressman and former Union minister of state for railways, Bhakta Charan Das lodged an FIR with the Bhawanipatna police station after he received a postcard which threatened to send a bullet through his chest if he continued to oppose Vedanta Alumina.

Das, whose outfit Green Kalahandi is leading the Dongaria Kandh tribal agitation against the bauxite mining of Niyamgiri mountain in Kalahandi district, has planned a massive protest through human chain in the last week of December.

In the last three years, Das has staged 25 protests against Vedanta Alumina that is building the 1.4 million tonne alumina refinery at Lanjigarh. The project, which was stuck in litigation in the Supreme Court, cleared all the hurdles in August after the apex court said the company can go ahead with mining of the mountain for bauxite.

The postcard purportedly from Maoists sent to Das at his Bhawanipatna residence in Kahandi district said they tried to contact him on November 18, but failed. "If you oppose Vedanta you would be hit by bullet in any rally you organise in future," the letter said. But the postcard did not bear the names of any Maoist functionary.

The letter which castigates Das for opposing the project accused the Congressman of trying to hoodwink the tribals. "However hard you may try, you will never win an election, because you are from Congress that looted the state for 40 years," the letter said.

Das said the letter can never be from Maoists and seems to be handiwork of Vedanta. "First they tried to bribe me and when they failed they resorted to the cheap tactics.

The letter seems to have been written by people who know me. They want to create confusion among tribals who are coming for the December gherao of Niyamgiri. My presence in the agitation would prove to be difficult for the company," Das told The Indian Express.

He added that he has sent copy of the FIR to the Kalahandi SP, Director General of Police and state Home Secretary. "I have not been given security. I have never asked for it. I am not bothered about the threats as I have always been a revolutionary throughout my life," he said.

Vedanta Alumina officials could not be contacted for their response to the allegation of Das.