Sunanda Pushkar and Shashi Tharoor
The unnatural nature of Pushkar's death is the reason for registering a murder case.Reuters

The BJP Tuesday asked Delhi Police to carry out a "free, fearless, and favourless" investigation in the death of Sunanda Pushkar, wife of Congress leader Shashi Tharoor.

"The BJP's mindset is investigative agencies should do their job freely, fearlessly, without favour. And the truth should come out," said Bharatiya Janata Party spokesperson Nalin Kohli.

Based on the final medical report from AIIMS that called it a case of "unnatural death", Delhi Police Tuesday registered an FIR against unknown people for murder under section 302 of the Indian Penal Code nearly a year after Pushkar was found dead in a luxury hotel in the capital.

Delhi Police chief B.S. Bassi said Pushkar was poisoned to death, but whether the poison was administered orally or injected into her body was still under investigation.

BJP leader G.V.L. Narasimha Rao said the confusion stood resolved as it was now clear that Pushkar's death was a case of murder and not a suicide, as it was perceived initially.

He said the case was not an act of political vendetta by the ruling party, and the BJP would see it as just "another case of crime".

"There is no politics in this, so BJP would simply see this as another case of crime. Delhi Police is quite capable of handling this investigation and will ensure punishment for the accused."

BJP's Subramanian Swamy, however, had a different view.

Calling it "not an ordinary murder of passion", Swamy alleged Pushkar was silenced for attempting to tell the truth.

He found "conspiracy of silence" in this "big murder" involving money that, he claimed, could tarnish the image of high-powered people who were involved in the incident.

Tharoor was minister of state for human resource development in the Manmohan Singh government at the time his wife was found dead under mysterious circumstances at the Leela Palace hotel here Jan 17, 2014.