9:55 pm: "Shashi Tharoor baiters are crowing - we know who you are, we know what you did. Tharoor may sleep a dash uneasily tonight," says Shobhaa De.

Shashi Tharoor baiters are crowing : We know who you are. We know what you did! Tharoor may sleep a dash uneasily tonight. — Shobhaa De (@DeShobhaa) January 6, 2015

8:30 pm: Delhi Police will send Sunanda's viscera samples to a laboratory either in Britain or the US to identify the poison including whether it could be radioactive isotopes that cannot be detected in Indian labs, as per PTI.

6:40 pm: Achuthanandan asks Congress' central leadership to tender an apology to the people of Kerala for fielding Tharoor for the second time despite him coming under the shadow of suspicion for the death of his wife. "Tharoor's continuance as an MP is legally and morally wrong since the Delhi police had made it clear that he would be questioned in the case," Achuthanandan said, as per PTI.

4:45 pm: Former top cop Kiran Bedi says the evidence reveals that Sunanda was murdered for a reason and the important question is who was benefiting from her death.

4:20 pm: The BJP expresses hope that the investigation in Sunnada death case will be completed soon. BJP leader GVL Narasimha Rao says the probe must reach a conclusive end.

4:05 pm: Shashi Tharoor expresses shock over police filing a murder case in connection with Sunanda Pushkar's death.

Tharoor issues a statement on his official Facebook page. Here's what he says:

"I am stunned to hear that the Delhi Police have filed a case of murder against unknown persons in the demise of my late wife Sunanda. Needless to say I am anxious to see this case is investigated thoroughly and continue to assure the Police of my full co-operation. Although we never thought of any foul play in the death of my wife, we all want that a comprehensive investigation be conducted and that the unvarnished truth should come out.

In the meantime I join all members of Sunanda's family in asking for full information about the basis on which the Police have come to this conclusion. We have not been provided with copies of the postmortem report and other reports of the inquiry like the CFSL report till date. We repeat our request for a copy of these reports to be provided to us immediately."

3:55 pm: Another Congress leader Abhishek Manu Singhvi says the case should not be sensationalised.

3:40 pm: Congress leader Rashid Alvi questions the delay in registering an FIR in the Sunanda Pushkar death case and says that the police should investigate the matter honestly.

"I always say that law will take its own course, but why is the case being registered after a year? I think that the investigation should be done honestly. It is the responsibility of the police to complete the investigation," says Alvi.

"It is very surprising that after a year the police have registered this case under Section 302. There are so many questions that are arising. Why have they come to this conclusion now? This is the reason people are doubtful about their investigation," he says.

3:15 pm: BJP leader Subramanian Swamy expresses happiness over Delhi Police filing an FIR in Pushkar's death case. He says, this was a murder of involving money.

Swamy says "The only crime Sunanda committed was that she wanted to tell the truth. Even the hotel where the incident took place has to be investigated. I want to establish a principle, no matter who it is. There is a right to life. No one can deprive it."

Swamy further accuses Shashi Tharoor of being a liar. He says the more the Congress leader speaks, the more trouble he will get into.

2:55 pm: Congress leader Renuka Chowdhury reacts to the sensational revelation in Pushkar death case, says Delhi Police must question BJP leader Subramanian Swamy as to how did he get the information on her death.

Renuka says at present it would be improper to name Shashi Tharoor as an accused and demanded thorough probe in the case.

2:50 pm: Sunanda Pushkar's cousin Ashok Kumar says they always knew that this was a case of murder.

2:30 pm: Delhi Police registers a case of murder after a medical report said Sunanda Pushkar's death was unnatural and was caused due to poisoning.

Addressing the media, Delhi Police Commissioner BS Bassi says, "Sunanda died due to poisoning. Whether the poison was given orally or injected into her body is being investigated." Bassi adds that the report from the All India Institute of Medical Sciences was received on Dec 29.

In consequence, Delhi Police have filed a case of murder in Sunanda Pushkar's death, Bassi informs.

"On 29th December, the medical board of AIIMS has given us a report. The main thing they have informed us is that the death is unnatural and not natural. Secondly, it is due to poison that could have been taken orally or injected and they have told us other things as well," Bassi says.

Information was gathered and information was submitted. Now, a final report has been given which says that the death was not natural, death was due to poisoning," Bassi says.

"Unfortunately, the quantification of poisons cannot be done in India, so we will be sending the samples abroad. In order to do so, we had to register a case; thus we have done the needful. We have registered an FIR under IPC Section 302," he further informs.