The wife of Indian minister Shashi Tharoor, who was found dead in a luxury hotel after accusing her husband of having an affair, is thought to have died of a drug overdose. Tharoor, 57, the junior human resources development minister, found his wife Sunanda Pushkar dead on Friday in her five-star hotel room in New Delhi when he returned from a Congress party meeting. An autopsy report, submitted on Monday to a magistrate who would investigate her death, cited a drug overdose as the cause of death, the Press Trust of India reported. Magistrate Alok Sharma would not reveal further details of the report and said he would study it with statements from others, including Tharoor. "On this basis, I will conclude what was the cause of death and submit a report to the police," Sharma was quoted as saying. Tharoor has pledged full co-operation with investigations into his wife's death, which came after she exposed his alleged affair with Pakistani journalist Mehr Tarar on Twitter. The death was a tragic twist in a tale of apparent marital strife that has been played out in full view of the public in India's newspapers and on social media. Pushkar, 52, died an "unnatural, sudden death", said doctors who performed an autopsy on Saturday, adding that more tests were needed to determine the exact cause. Her body had "some physical injuries", but it was unclear whether they were related to her death, said Sudhir Gupta, one of three doctors who performed the autopsy. Her body was cremated according to Hindu rites over the weekend. The accusations of an affair first surfaced last Wednesday, when unusual messages started appearing on the Twitter account of the three-times-married Tharoor, who is also a novelist and a prolific tweeter. They revealed private exchanges purportedly between the minister and Tarar, in which she professed her love for him and he said his wife had discovered their relationship. Tharoor quickly responded by saying his Twitter account had been hacked. However, Pushkar then told two newspapers that she was the author of the messages. Tarar strongly denied having an affair with the former highflying UN diplomat. Seeking to draw a line under the Twitter row, Tharoor issued a statement on Thursday in which he blamed unauthorised tweets and distorted media reports for the "unseemly controversy". The statement said the couple were "happily married". Tharoor found his wife dead the next day.