NEW DELHI • Ms Sunanda Pushkar, the wife of former high-flying United Nations diplomat and former Indian government minister Shashi Tharoor, may have died of poisoning due to an overdose of the anti-anxiety drug Alprax, a report released by an Indian medical board has said.

Ms Sunanda Pushkar, 52, was found dead in a five-star hotel on Jan 17, 2014, by Mr Tharoor, a former minister in the previous Congress government. She had accused him of having an affair with a Pakistani journalist at the time.

Ms Pushkar, married to Mr Tharoor since 2010, had been taking medication for various illnesses and early autopsy results suggested she may have overdosed on anti-depressants and sleeping pills.

But the police last year said they believed that Ms Pushkar ingested or was injected with poison, though they have yet to name a suspect.

A new report into her death released by the medical board of Delhi's All India Institute of Medical Sciences (AIIMS) has now "unanimously" concluded that the cause of death was poisoning, national daily The Indian Express reported on Thursday.

The AIIMS report had analysed the findings made by the United States Federal Bureau of Investigation (FBI). Samples were sent to the FBI as Indian labs did not have the facility to test certain types of poison.

The report ruled out radiation poisoning as a cause of death.

It stated that the circumstantial recovery of empty Alprax strips (27 tablets) "and report of (the) FBI, which shows (the) presence of Alprax in (the) stomach and its contents, spleen, liver, half of each kidney, blood sample, as well as urine wet clothing, bed cover and bed sheet, confirmed the death due to 'excessive ingestion of tablet alprazolam'". Alprax is a common name for alprazolam.

The paper had last week also reported that an Alprax overdose was the likely cause of her death. "It appears that she took multiple tablets of Alprax, which generated poison in her body which finally killed her. We are now probing whether she took the tablets or was given a high dose," a source told the paper.

The report also stated that Alprax and lidocaine - an antiarrhythmic drug for the heart which may cause fatality if administered intravenously - were found in her viscera (intestines) samples.

It said further investigation needed to be done to determine how it entered her body.

Ms Pushkar's death had triggered speculation that she had committed suicide after being humiliated by her husband, Agence France-Presse reported.

Her death dealt a severe blow to the image of Mr Tharoor, who was a Cabinet minister at the time and remains a Member of Parliament for the opposition Congress party.

Mr Tharoor had also served as under-secretary general during Mr Kofi Annan's leadership of the UN.