Delhi Police has urged the Director General of Health Services to form a medical board to examine test reports in connection with Sunanda Pushkar's death.

A letter was sent to the DG Health Services after the Special Investigation Team probing the case failed to draw any conclusion from the AIIMS medical board's opinion vis-a-vis the FBI report on Pushkar's viscera sample and other evidence in the case, a police source told PTI.

The SIT had earlier written to the AIIMS medical board seeking further clarification on their opinion, but the response of the board is still awaited.

Even a day before his retirement, Delhi Police chief BS Bassi had said the case will be taken to its logical conclusion.

The AIIMS medical board's opinion on the FBI report had suggested that Sunanda, wife of Congress MP Shashi Tharoor, died of poisoning with the presence of Alprax found in her stomach.

Last month, the police questioned Tharoor for the third time in connection with his wife's death.

51-year-old Sunanda was found dead in her room at a five- star hotel in south Delhi in January 2014. A case of murder was registered in the matter around one year later following which her viscera sample and some other evidence in the case were sent to an FBI laboratory in the USA.