Hursit Tolon was already under arrest on charges he was part of a network of military officers who plotted to overthrow the government, Today's Zaman reported Sunday.
Ozal allegedly died of heart failure at an Ankara hospital while in office. After a number of witnesses testified he died under suspicious circumstances, Ozal's body was exhumed last year.
Testing found poisonous substances in his organs and tissues, but members of a council overseeing the investigation were unable to determine conclusively the toxins were the cause of death.
Any charges in Ozal's death must be filed by April 17, when the statute of limitations will expire.
Notable deaths of 2014 [PHOTOS]