Sources said that police will decide its next step after it gets the final report from the American investigative body.
DCP (South) Prem Nath had gone to the US last month to deliver the sample of Sunanda's viscera to the FBI labs.
Investigators had sent the viscera samples there after AIIMS doctors had said that Indian labs lacked facility to identify the poison which caused her death.
The cause of death, termed "poisoning" by a panel of AIIMS doctors has remained the biggest mystery of the case as they could not specify the kind of poison and the way it reached Sunanda's body.
"The Special Investigating Team (SIT) which is probing the case is waiting for FBI's report in the case. A considerable amount of investigation has been completed in this case," Bassi told reporters.
Questioned about reports suggesting that the Delhi Police has contacted Pakistan High Commission regarding Pakistan journalist Tarar's questioning, Bassi said, "We haven't established any contact with the Pakistan High Commission regarding the questioning of Mehr Tarar, these reports are untrue."
As far as examining of Tarar is concerned, it will be done if required, he added.
Bassi had on March 12 said Tarar was a "relevant link" in the case and the SIT probing Sunanda's death may question her soon.
A day before the former Congress Union Minister Shashi Tharoor's wife was found dead in a luxury hotel here in January last year, she had a spat with Tarar on microblogging website Twitter over the latter's alleged affair with Tharoor.
On her part, Tarar had said that she was ready to answer questions if it would help the police piece together the sequence of events.
The police chief also said investigators have also asked the Federal Bureau of Investigation (FBI) in the US to complete examination of Sunanda's viscera as soon as possible.
Tharoor was questioned by the investigators for three times last month which was focused on the IPL controversy, which broke in early 2010 when he was the Minister of State for External Affairs.
52-year-old Sunanda was found dead in her suite at a five star hotel in south Delhi on the night of January 17 last year.
There were allegations that Tharoor "misused" his office to ensure that Rs 70 crore, equivalent to a 19 per cent stake in IPL Kochi franchise Rendezvous Sports, was paid to Sunanda, a charge denied by him.
Tharoor had submitted to the SIT last month some computer data -- which included emails and other information in digital form -- pertaining to the communication he had had with various individuals and authorities before and after the mysterious death of Sunanda.

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