Sunanda Pushkar, 51, was found dead at the luxurious Leela Hotel in Delhi in January 2014
Sunanda Pushkar, wife of Congress lawmaker Shashi Tharoor, did not die due to poisoning by polonium or any other radioactive substance, the Federal Bureau of Investigation (FBI) in the US has concluded.
The FBI report sent to the Delhi Police says no radioactive substance has been found in Ms Pushkar's body. It is being examined by a special investigation team.
Sunanda Pushkar, 51, was found dead at the luxurious Leela Hotel in Delhi in January 2014. For a year, her death was considered a case of suicide, but earlier this year the Delhi Police claimed that Ms Pushkar was poisoned and registered a murder case against unknown persons.
Her viscera samples were sent to the FBI lab in Washington in February this year after a panel of doctors from Delhi's All India Institute of Medical Sciences concluded that the poison could not be detected in Indian labs.
The police has not named any suspects in the case but has questioned Mr Tharoor multiple times. It has also conducted polygraph tests on six people, including Narain Singh, Mr Tharoor's domestic help, driver Bajrangi and family friend Sanjay Dewan, all listed as prime witnesses.
Delhi Police Commissioner BS Bassi told NDTV today that a decision on whether to call Mr Tharoor again for questioning will be taken after the medical board involved in the investigation into the case gives its opinion.