Pushkar was found dead in a hotel room last year on January 17. The autopsy report stated that her death was due to poisoning, but there was no clarity on whether it was a homicide or suicide.

AIIMS in its subsequent report sent in September named a few poisons which could not be detected easily by forensic laboratories in the country.

In a letter to Delhi Police Commissioner B.S. Bassi dated Nov 12 and accessed by the media Wednesday, Tharoor urged the police chief to take action against the concerned officer.

Tharoor said that four Delhi Police officers interrogated his domestic help Narayan Singh last month - for 16 hours Nov 7 and for 14 hours Nov 8.