Öksüz was first detained just outside Akıncı Air Base, a military base in the capital Ankara after the coup attempt was foiled. The base was sort of a command center for the putschists with warplanes taking off from there striking strategic locations.
However, hours after his detention, a court controversially ordered his release with judicial control. Öksüz was last seen in Sakarya, the northwestern city where he taught at a university, before his disappearance. Months of manhunts across Turkey failed to yield results and authorities concluded that he fled abroad.
Referred to as the "black box" of FETÖ for his intricate ties to senior cadres and prominent role in the coup attempt, Öksüz reportedly acted as the Air Force leader for the terrorist group.
FETÖ leader Fetullah Gülen and Öksüz are being tried in absentia in several coup cases. Both men face multiple life sentences for their suspected role in the coup attempt that came three years after FETÖ members in the judiciary and law enforcement tried two other unsuccessful coup attempts.