Sunanda's body has been sent for post mortem to AIIMS.
Delhi Police forensic experts and crime branch officials rushed to the spot and sealed the hotel rooms. The hotel cctv showed that Sunanda was last seen in the hotel lobby.
Prime Minister Dr Manmohan Singh rang up Tharoor and expressed his condolences.
Delhi Police is questioning the couple's driver and domestic servants.
Police said, the initial appearances inside the hotel room indicate it was a case of suicide.
Sunanda was involved in a twitter spat with Pakistani journalist Mehr Tarar recently.
She had accused Mehr of stalking her husband Shashi Tharoor.
Her last message on a networking app was “Don't take life too seriously, no one gets out alive.”
