Demirel, who served as Turkey's ninth president, labeled as empty talk media reports Ozal died from poisoning and not a heart attack, Today's Zaman reported Tuesday.
Turkey's Council on Forensic Medicine is finalizing a report on its investigation of Ozal's death, which will be turned over to the public prosecutor's office next month.
Ozal's remains were exhumed from an Istanbul grave in October for toxicological testing.
He died at the age of 65 while still in office.
There was no post-mortem at the time of his death and blood test results were reported missing.