New Delhi, Jun 2 (NDTV): The doctor who conducted the post-mortem on Sunanda Pushkar, wife of Congress lawmaker Shashi Tharoor, has written to Health Minister JP Nadda alleging that he was pressured to give a false report of natural death and was "victimised by the previous government," when he refused to do so.

In his letter - which the Health Ministry said it is yet to receive - Dr Sudhir Gupta, former forensic director of the All India Institute of Medical Sciences or AIIMS has alleged a "tacit understanding" between AIIMS director MC Mishra and Mr Tharoor, who was a minister in the previous Congress-led UPA government, "for making a tailor-made post-mortem report."

"I was asked by Dr Mishra to give a post-mortem report of late Sunanda Pushkar as natural death, which was contrary to the findings," Dr Gupta writes, and adds, "But I did not succumb to pressure and gave the faculty report as an upright official." NDTV has access to a copy of the letter.

Dr Gupta had moved the Central Administrative Tribunal with similar allegations after a move to replace him as the forensic director. In March this year, the tribunal quashed his plea and he moved the Delhi High Court.

An AIIMS spokesperson said Dr Gupta's allegations are "baseless."

"No extraneous pressures was ever put on Prof Sudhir Gupta with regard to his medical opinion in any case," the spokesperson said. "The procedure is that the Head of Department is recommended by the Director and AIIMS, following procedure, has applied to the High Court for its permission to appoint the senior-most faculty as Head of Department," he said.

Sunanda Pushkar was found dead in a five-star hotel in Delhi in January 2014. For a year, her death was considered a case of suicide, but earlier this year the Delhi Police filed a murder case.

This was based on evidence from an AIIMS medical board that conducted her autopsy, concluding that the circumstantial evidences were "suggestive of alprazolam poisoning". Dr Sudhir Gupta was in charge of the board.