The death of Faiz Usmani in a hospital after being questioned in connection with July 13 serial blasts here prima facie appeared due to natural causes, said Dr T P Lahane, Dean of government-run J J Hospital where the post mortem was performed.
The final report was yet to be prepared and viscera and other organs have been sent to laboratory for chemical analysis, Lahana said.
Preliminary post mortem report suggested that Usmani had suffered a heart attack yesterday but this was not the first time. Earlier too, he had suffered heart attack, Dr Lahane pointed out.
90 grams of blood clot was found in his brain. Also, no injury marks were found on Usmani's body, he said.
Usmani, brother of alleged Indian Mujahideen (IM) member Afzal Usmani, who is currently lodged in jail for his role in the 2008 Gujarat blasts, was picked up for questioning on July 16 by Chembur's Crime Branch unit and was taken to a hospital at Sion at around 5:50 PM as he was not feeling well.
He died at 1:30am on Sunday while undergoing treatment for hemiparesis and hypertension in Lokmanya Tilak Hospital, doctors said.
Usmani's family alleged he was tortured in custody, a charge denied by Mumbai Police.
Maharashtra DGP Ajit Parasnis had ordered a CID inquiry into his death.