The final autopsy report of National Conference worker Haji Syed Yusuf has not found any evidence of poisoning or injuries and said his death was caused by massive heart attack.
The final report by Principal of Government Medical College which was conducting other tests including viscera said Yusuf died of "cardio-vascular respiratory failure" and that there were no signs of any external or internal injury, official sources said.
The report, which is likely to be submitted to Additional District Magistrate Mohammed Akbar, says that it has not detected presence of any poison in the blood, they said.
The preliminary report had also suggested that there were no traces of any poison in the blood and food samples taken from the deceased during postmortem, the sources said.
Yusuf had died on September 30 and it is mandatory under Section 176 Criminal Procedure Code to hold a magisterial inquiry into any death in police custody.
The initial report has also said he had no external injuries to suggest any torture as alleged by the deceased's family.
The magisterial inquiry may shape the future course of action to decide whether the death was natural or whether it needed any further probe, the sources said.