Mystery surrounded the death of Sunanda Pushkar, wife of junior HRD minister Shashi Tharoor, with doctors at AIIMS Saturday saying that the 52-year-old died an "unnatural, sudden death" with her body bearing "injury marks".

 

 Police investigators, however, said that "it could be a case of drug overdose or overdose of sleeping pills" but hastened to add that things would be clear only after the detailed autopsy report.

 

 Police also said that the couple had a "verbal spat" during their flight from Thiruvananthapuram to Delhi on Tuesday. 

 

 In the hotel too they were arguing, which was disclosed by the housekeeping staff to police during investigation. 

 

 Tharoor, 57, who was himself admitted to the All India Institute of Medical Sciences (AIIMS) for 11 hours after he complained of chest pain Friday, broke down many times. He accompanied Pushkar's body in the ambulance to their residence at 97, Lodhi Estate and then later to the crematorium.

 

 Tharoor, the minister of state for human resource development, and Sunanda's son from an earlier marriage, Shiv, lit the funeral pyre as close family and friends bid a tearful adieu to Pushkar, whose body was found in a luxury hotel in Delhi Friday night in mysterious circumstances.

 

 Her death came barely 24 hours after she and Tharoor declared they were "happily married" following public airing of tweets that hinted at an extra-marital relationship and the alleged involvement of a Pakistani woman.

 

 Congress chief Sonia Gandhi visited Tharoor's residence after the cremation. Earlier too many of his cabinet colleagues dropped in to pay their condolences. Prime Minister Manmoahn Singh also condoled the death, saying that "we are with you in this hour of grief".

 

 Speaking to reporters after two-hour long postmortem, Sudhir Kumar Gupta, head of the department of forensic medicine at AIIMS said: "After post-mortem examination, we found that it was a case of sudden unnatural death.

 

 "There were certain injury marks on the body. Since the investigating agency is probing the issue and there are certain issues with the injury, the details cannot be revealed," Gupta, who was part of a three-member team that conducted the autopsy, added.

 

 However, doctors said the real cause of death can only be ascertained once the laboratory test result of biological samples are received.

 

 He also said that samples for toxicological analysis, which means ruling out any poison and pathology of the heart, has been preserved.

 

 But police sources told IANS that the death could be "a case of drug overdose".

 

 Sleuths scanned CCTV footage of the hotel where her body was found and questioned staff, who told police about the couple's constant arguments. The couple had moved to The Leela Palace hotel in south Delhi Thursday as their house was being painted.

 

 Police will also take a statement from Tharoor, the Congress MP from Thiruvananthapuram. 

 

 Doctors at a Kerala hospital where Pushkar was undergoing treatment said that she did not had any grave illness. The couple returned from Kerala after her three-day stay in KIMS Hospital.

 

 At the Lodhi Road crematorium, Pushkar's son and father P.N. Das were inconsolable. Both at the mortuary and at the cremation ground Pushkar's son broke down several times. 

 

 But whenever Tharoor tried to console him, Shiv moved away. This happened many times.

 

 He and Tharoor stayed till the last. But when they left, Shiv again returned and  whispered to his grandfather: "This is an end." And he stayed till the end. 

 

 A magisterial enquiry has already been ordered in the death as the couple got married in August 2010. It was the third marriage for both.