The All India Institute of Medical Sciences on Friday said that businesswoman Sunanda Pushkar died after overdosing on an anti-anxiety drug. An AIIMS medical board sent a report to the Delhi Police that reaffirmed the Federal Bureau of Investigation’s conclusion that Pushkar, wife of Congress MP Shashi Tharoor, did not die of poisoning from polonium or any other radioactive substance. Her visceral samples were sent to the United States for testing after a post-mortem examination had found traces of radioactive isotopes in her body.

The medical board also criticised the Central Forensic Science Laboratory and Forensic Science Laboratory for failing to detect poisoning in Sunanda’s body. The FBI report was sent to the AIIMS medical board for its opinion, after the Delhi Police failed to draw any conclusion from its findings. Delhi Police Commissioner BS Bassi confirmed they had received the report and said, “Radiation levels found were within an acceptable range. We will investigate further and share details when we can.”

Pushkar’s death, in a five-star hotel in Delhi in January 2014, has been shrouded in mystery. The Delhi Police is likely to continue investigating the possibility of Pushkar's death being a suicide. India Today reported that experts believe the amount of drugs found in her system was too high to have been forcibly administered. Tharoor is also expected to be summoned for another round of questioning.