The Special Investigation Team (SIT) probing into the mysterious death of Sunanda Pushkar, wife of Congress party leader Shashi Tharoor, has carried out the polygraph test of three key witnesses, Narain Singh, Bajrangi and Sanjay Dewan, sources said. 

Narain is the domestic help and Bajrangi is the driver. SK Sharma, Vikas Ahlawat and Sunil Takru have also undergone the lie detector test in connection with the case.

However, Rajiv Dewan, defence counsel of Sanjay Dewan and investigating officer of the case, refused to comment on the recent updates.

A Delhi court on May 20 had permitted the SIT to conduct the polygraph test of the three witnesses after they agreed to undergo a lie-detector test during a hearing.

The lie-detector test was sought by the Delhi police, which is investigating Pushkar’s death. 

In its detailed report submitted to the local court on May 15, the Delhi Police mentioned that three witnesses Narain, Bajrangi and Sanjay Deewan were present at the Hotel Leela Palace just before Pushkar&’s death but they alleged that they lied.

In its plea the SIT claimed that on January 17, Tharoor’s close friend Sanjay Dewan came to the hotel at 5 pm and were there till Pushkar was found dead. He could not give plausible reason for cancelling his trip to Mumbai and his coming to the hotel in Delhi.

The SIT also said that Dewan did not wake Pushkar up for two-and-half hours and he also could not explain why he preferred to call Dr. Rajan Mohan, who came all the way from Patel Nagar, over the hotel doctor who could come within a short span of time.

It alleged that Dewan did not give proper explanation for sending driver Bajrangi to bring Dr. Mohan without even seeing Pushkar in her room.

In its plea, the SIT said that Dewan did not produce his cell phone which was required to retrieve the text messages exchanged between him and Tharoor, as per the call details. 

"It shows that he is hiding the material facts related to this case," said the SIT. 

Also, Bajrangi, Narain and Sanjay Dewan did not disclose how injury marks appeared on Pushkar’s body while all three were present in the room along with Tharoor and Pushkar, the SIT said.

The SIT report also questioned why Tharoor and Sunanda stayed at the hotel when repair work at their home had been completed before their arrival in Delhi on January 15, 2014. It claimed that the three suspects remained silent on a power cut on January 17, 2014 around 7 pm in room No. 345 at the hotel just before Pushkar was found dead.