New Delhi: Union minister Mukhtar Abbas Naqvi said on Thursday that the "missing documents" of the Ishrat Jahan encounter case amounted to "anti-national activity" and those involved will be punished. Naqvi's reaction came in the wake of an Indian Express report that said a bureaucrat tasked with inquiring into the "missing documents" of the Ishrat Jahan encounter case was found tutoring a witness. "All efforts are being made (to find out the truth about the missing papers). It's a criminal conspiracy and an anti-national activity. Anyone involved will not be allowed to go scot free," Naqvi told reporters here. Chidambaram has been accused by the BJP of filing, as then Home Minister, a second affidavit in September 2009 that dropped references to Ishrat Jahan’s alleged Lashkar-e-Taiba links and suggested a CBI probe into her killing in an alleged fake encounter. The BJP alleged that Chidambaram amended an earlier affidavit to suit the Congress stand that Ishrat Jahan was innocent and shot in cold blood on June 15, 2004 with three others, on the orders of the Gujarat government, then headed by Narendra Modi. Union Home Minister Rajnath Singh said some documents went missing related to the case and tasked Additional Secretary (Foreigners) B.K. Prasad to conduct a probe. Prasad submitted his inquiry report to the Home Secretary on Thursday. The Indian Express report says that Prasad told Ashok Kumar, a director in the Home Ministry in 2011, what he was going to be asked regarding the "missing documents" and what he should answer. The newspaper also put an audio recording of the purported conversation between Prasad and Ashok Kumar on its website. Now, the government may order a CBI inquiry to find out how and when the papers related to the Ishrat Jahan case went missing, informed sources said.