The 3-member Medical Board, which handed over the report to the SIT, had opined that Fiza had died due to poisoning by aluminium phosphide in the presence of ethyl alcohol.
The SIT officials did not comment on the report citing technical reasons.
SIT chief S P Swarndeep Singh was not available for comments. A senior official, on condition of anonymity, said they were not in a position to comment as they were seeking some clarifications.
The post-mortem report, prepared by doctors P S Bhatti, Neera Verma and Sukhwinder Kaur, said "the cause of death in our opinion, is poisoning due to aluminium phosphide in the presence of ethyl alcohol."
The highly decomposed body of 39-year-old Fiza, the estranged second wife of former Haryana Deputy Chief Minister Chander Mohan, was found at her Mohali residence a month ago.
The police had not found any suicide note from Fiza's house.
Fiza had shot into limelight four years ago following her controversial marriage to Chander Mohan, son of former Haryana Chief Minister Bhajan Lal.