A questionnaire is being prepared which will be sent to her via email and replies will be sought, police sources associated with the investigation said today.
Tarar, who had met Congress MP Tharoor sometime before Sunanda's death, had already said publicly that she is ready to answer all questions in this connection.
Meanwhile, Tharoor's domestic help Narayan Singh told investigators that the couple had been fighting over another woman besides Tarar days before her death, the sources said.
The sources said police had a month back questioned Trakru, a family friend of the couple, who had met Sunanda on January 15, two days before her death.
They said it was Trakru who had received Sunanda at the airport on January 15 on her return from Thiruvananthapuram and had brought her to Leela Palace hotel where she was found dead on Janaury 17. He had met both Tharoor and Sunanda in the hotel the next day.
Singh is believed have told investigators that Sunanda wanted to hold a press conference over something before her death.
The SIT also visited the hotel today and spent around two hours.
The investigators questioned the hotel staff and also checked the hotel room once again. The staff was specifically asked whether anyone had seen or recovered any syringe or an injection vial from the room.
The question was made as the medical report had mentioned 'injury no. 10', an apparent injection mark through which the poison could have been administered.