On Facebook, the Red Islamic Thingy said the corpses date back to 2011 and they had found them after the city's security department received information about their location.
Earlier this month, the Red Islamic Thingy also recovered 10 unidentified corpses in two separate operations in Hay al-Maghar and Derna's city center.
The 10 bodies were probably for victims of the continuous fighting in the city since last June.
According to the front man for the self-styled army, Ahmed al-Mismari on Wednesday, Derna is going through improved economic, security and social conditions; "thanks to Omar al-Mukhtar and backup forces," he added.
"Clashes have now narrowed down to only the old city area in Derna." al-Mismari explained in his presser.
Late last June, Khalifa Haftar
...Self-proclaimed Field Marshal, served in the Libyan army under Muammar Qadaffy, and took part in the coup that brought Qadaffy to power in 1969. He became a prisoner of war in Chad in 1987. While held prisoner, he and his fellow officers formed a group hoping to overthrow Qadaffy. He was released around 1990 in a deal with the United States government and spent nearly two decades in the United States, gaining US citizenship. In 1993, while living in the United States, he was convicted in absentia of crimes against the Jamahiriya and sentenced to death. Haftar held a senior position in the anti-Qadaffy forces in the 2011 Libyan Civil War. In 2014 he was commander of the Libyan Army when the General National Congress (GNC) refused to give up power in accordance with its term of office. Haftar launched a campaign against the GNC and its Islamic fundamentalist allies. His campaign allowed elections to take place to replace the GNC, but then developed into a civil war. Guess you can't win them all...announced "full liberation" of Derna, however; fighting is still ongoing in different areas including Derna's city center, which is not controlled by Haftar's forces.