Sunanda Pushkar, the wife of Indian diplomat-turned-politician Shashi Tharoor, who was found dead in a New Delhi hotel room last January, was murdered, a senior police official said Tuesday, according to local media reports. Local police have now registered a murder case and are reportedly sending forensic samples abroad for testing.

Pushkar was found dead in a room at The Leela Palace hotel in the Indian capital on Jan. 17, 2014. A few days before her death, Pushkar had written messages on social media website Twitter, hinting that her husband was involved with Pakistani journalist Mehr Tarar. Her death was unnatural and occurred due to poisoning, Hindustan Times (HT), a local newspaper reported Tuesday, citing Delhi Police Commissioner B.S. Bassi, adding that the substance that may have caused the poisoning has not yet been identified.

"We are taking all necessary measures in the case. It is clear that Sunanda Pushkar's death was not natural," Bassi reportedly said, adding: "She died due to poisoning. Whether the poison was given orally or injected into her body is being investigated."

Pushkar was a Dubai-based entrepreneur before she married Tharoor in 2010. Two days before her body was found, she had said in a televised interview that the couple was “happily married,” NDTV reported. Tharoor, who served as Under-Secretary General during Kofi Annan's tenure at the United Nations, is also a renowned author.

"I am stunned to hear that the Delhi Police have filed a case of murder against unknown persons in the demise of my late wife Sunanda. Needless to say I am anxious to see this case is investigated thoroughly and continue to assure the Police of my full co-operation. Although we never thought of any foul play in the death of my wife, we all want that a comprehensive investigation be conducted and that the unvarnished truth should come out,” Tharoor said, in a statement, on Facebook.

While Tharoor sought copies of the post-mortem and other inquiry reports, politicians have questioned why it took the police a year to register a case, NDTV, a local news network reported.

"I always say that law will take its own course, but why is the case being registered after a year? I think that the investigation should be done honestly. It is the responsibility of the police to complete the investigation," Rashid Alvi, a leader of the Congress party of which Tharoor is a member, said, according to Zee News, a local news network, adding: “It is very surprising that after a year the police have registered this case.”