New Delhi, Jan 26 (IANS): Two units of Delhi Police are at loggerheads to proceed with the investigation into the mysterious death of union Minister Shashi Tharoor's wife Sunanda Pushkar.

According to police, the Crime Branch has refused to initiate a probe into the case and it has been transferred back to the South District police. The case was handed over to the Crime Branch Jan 23.

The body of 52-year-old Pushkar was discovered by her husband in a south Delhi's five-star hotel room Jan 17. She was staying in the hotel room with her husband as their government accommodation was being renovated.

The case was handed over first to a Sub-Divisional Magistrate as mandated by law since Tharoor was married to Pushkar for less than seven years. The SDM conducted an inquiry and submitted a report to South District police within a week.

On the basis of the post-mortem examination, which stated that Pushkar's death was caused by poisoning, the SDM suggested police should investigate the matter.

The autopsy report also mentioned that there were more than a dozen injury marks on Pushkar's body, though these were not fatal.

A day after the probe was to be started by the district police, the investigation into the case was given to the Crime Branch. But officials have declined the probe, stating that there is nothing left in the case.

A senior officer in the Crime Branch who did not wish to be named told IANS that the district police were trying to hand over the case when nothing much was left in it.

Another officer said the unit is short in staff these days and could not take more cases for investigation.

"There are already several unsolved cases pending in the cold cases cell of the Crime Branch," said the officer.

Meanwhile, the South District police officials did not respond to calls even after repeated attempts to contact them.

Pushkar was found dead amid rumours of her husband getting close to a Pakistan-based female journalist. A controversy broke out in the media when Pushkar tweeted on social media about her husband's relationship with the journalist.

Pushkar and Tharoor married in 2010.