The Indian media continues to speculate on the actual cause of death of the wife of a prominent minister on Friday, with most indicating drug overdose and suicide.

A team of three doctors, who conducted the autopsy on Sunanda Pushkar on Saturday declared the death in their preliminary report as “sudden and unnatural”, and ruled out poisoning or injuries sustained as possible causes.

The complete report is expected within a couple of days.

Delhi police officers probing the death were more forthcoming in private conversations to state that it was possibly a case of suicide, The Times of India reported.

Sunanda, 52, wife of Minister of State for Human Resource Development Shashi Tharoor was found dead about 8.30pm (Indian Standard Time) at a hotel room in New Delhi, two days ago.

An autopsy was carried out at the All India Institutes of Medical Sciences (AIIMS).

The autopsy indicated that Sunanda died of drug overdose, most likely a lethal combination of sedatives, some other strong medicines and perhaps, alcohol, said the English daily.

However, it was still not known whether the drug overdose was caused by inadvertent recklessness or by a premeditated desire to end life, said the report.

What's now more or less certain is that Sunanda was deeply distressed by her husband's friendship with Pakistan journalist Mehr Tarar, and had demanded six months ago that he snap all communication with her.

Whether this demand was met is uncertain because tweets between Tharoor and Tarar surfaced in public, two days before Sunanda's death, it said.

Press Trust of India’s report also suggested that a drug overdose could be a possible cause of death.

The Hindu in its news report headlined, 'Mystery behind death deepens', also quoted unknown police sources as saying that before her death, Sunanda had consumed some medicines.

While withholding the time of consumption or the names, a source said some pills were recovered from the room where the body was found, it reported.

Another daily, DNA, also reported on possible drug overdose, but gave specification that it could be anti-depression medicine.

The exact cause of Sunanda's death would be revealed only after obtaining toxicology and pathology reports from the respective laboratories, it said.

A sub-divisional magistrate will record Tharoor’s statement on Monday.

Tharoor, who left his job at the United Nations after unsuccessfully contesting election for the secretary-general's post, returned to India in 2008.

Sunanda was an Indo-Canadian businesswoman. She was a sales manager in the Dubai-based TECOM Investments, and co-owner of the India-based Rendezvous Sports World.

The high profile couple married in 2010.

Sunanda was cremated in New Delhi on Saturday evening.