The shocking revelation has been made by senior journalist and Sunanda's close friend Nalini Singh.
In her statement to the Delhi Police, Nalini Singh has reportedly said that a day before Sunanda had died, she had called her to tell that Shahshi Tharoor wanted to divorce her so that he could get married to Mehr Tarar, for the fourth time.
She has also said that the relations between Tharoor and Tarar had become so close that they wanted to get married soon after the Lok Sabha elections 2014.
Sunanda had also reportedly told Nalini that in last year June, Tharoor spent three days with Tarar in Dubai.
Sunanda's servant Narayan has also told police in his statement that the couple used to fight quite often.
Narayan has also revealed that Sunanda and Shashi had an ugly fight in Dubai as well. They also had an argument on January 15 in the flight when both were coming to Delhi from Kerala.
"Sunanda had taken Tharoor's mobile phone during the flight, which led to the argument", he said.
Aftee getting down from the Flight at the Delhi airport, Tharoor had left for a meeting while Sunanda had checked in at the hotel alone.
With the new twist due to the statements given by Nalini Singh and Sunanda's servant Narayan, Sunanda Pushkar's death mystery has taken a new turn,with Tharoor becoming one of the prime suspect behind her wife's sudden death.
Sunanda was found dead in the Room number 345 of the The Leela Palace hotel in Chanakya Puti in New Delhi on January 18, 2014 night.
Sunanda's death came as a huge shock to the nation as a day before, she was embroiled into a Twitter controversy, by exposing a series of tweets between her husband Tharoor and Tarar, which indicated an affair between them
However, both Tharoor and Sunanda had tried to downplay the controversy by posting a 'joint statement' on Tharoor's official Facebook page that "the couple was happily married, and that some personal comments not intended for publication had been misrepresented after being posted to Twitter."
But what made Sunanda's death, a case of foul play were the inconclusive autopsy reports. It could not be found out whether she committed suicide or was murdered.
Her autopsy reports had suggested that there were injury marks on her wrist and her death was unnatural but at the same time it was also reported that she may have died of drug overdose. Thus, the real cause behind her death could not be ascertained.
Sunanda's death once again took the suspicious turn when the AIIMS doctor Sudhir Gupta on July 1, revealed that he was "pressurised" to manipulate her autopsy report.