The bodies were found north of Kufra city, the attorney general said, while 76 migrants were freed "from forced detention."
Kufra is about 1712km from the capital Tripoli.
On Thursday, the Alwahat security directorate in the southeast of the country recovered 19 bodies from a mass grave in Jikharra area, and the Libyan Red Crescent recovered 10 bodies of migrants off Dila port in Zawiya city in the west after their boat sank.
Libya has become a transit route for migrants fleeing conflict and poverty to Europe, via the dangerous route across the desert and over the Mediterranean following the toppling of Muammar Gaddafi in a NATO-backed uprising in 2011.
"There was a gang whose members deliberately deprived illegal migrants of their freedom, tortured them and subjected them to cruel, humiliating and inhumane treatment," the attorney general said on its verified Facebook page.
It said that the authorities have begun conducting forensic tests to understand "the cause of their deaths."
The authorities have started documenting the testimonies of the survivors and have detained three suspects: a Libyan national and two foreigners, it added.
