Delhi Police Commissioner B S Bassi today said that although the report was expected earlier, the "well-trusted lab" would have to be given the time it requires.
"The forensic science lab will take the time it requires. There are certain processes and protocols for a chemical examination. I expect the report to come by next month," he told reporters here.
Sunanda's viscera samples were sent to the FBI lab in Washington in February to determine the kind of poison after an AIIMS medical board identified poisoning as the reason behind her death but did not mention the type.
The investigators hope both the viscera report and polygraph test reports would give a direction to the probe into the high-profile case.
Sunanda was found dead in a five-star hotel suite here on January 17 last year, a day after she was involved in a spat with Pakistani journalist Mehr Tarar on Twitter over the latter's alleged affair with Sunanda's husband - Congress leader Shashi Tharoor.
