Turkish authorities on Monday arrested three terror suspects, including an accomplice to Adil Öksüz, the Gülenist Terrorist Group’s (FETÖ) mastermind that helped organize the July 15, 2016, coup attempt.

Suspect Cihat Yıldız, who first hid and later helped Öksüz escape in the aftermath of the failed coup, was captured with Ahmet Hızal after being stopped at a police checkpoint in Istanbul.

The driver, revealed to be Adem Bora, fled the checkpoint and was later captured in an operation at his hideout in the city.

Öksüz was controversially released after his initial capture at a military base at the heart of the putsch bid on July 16. He is known to be a close aide to FETÖ ringleader Fetullah Gülen, who is based in Pennsylvania.

Yıldız hid Öksüz at a house in the Üsküdar district for nearly a week following July 16 and later smuggled him abroad with another FETÖ accomplice.

Yıldız served as the so-called general manager of FETÖ infiltrators within the Turkish Air Force Academy and had been a fugitive for the past eight years. Before the coup attempt, he worked as a teacher in FETÖ-affiliated schools.

Often going by the code-names "Bahadır, Oğuz, Cahit" within the group, Yıldız used FETÖ’s encrypted communication app, Bylock, where members send information and receive instructions and had an account in Bank Asya. This now-defunct lender was the heart of FETÖ's financial arm.

Moreover, Yıldız organized trips for convicts who wanted to flee abroad and provided so-called "gaybubet (absence) houses" for members who remained loyal to FETÖ after the coup.

"Gaybubet houses" are used as safe houses by wanted FETÖ members who often forge IDs and rarely step out to avoid capture. A former member who testified to prosecutors said that the group's "absence" houses increased from 75 to 560 across Türkiye. Authorities believe that number might be even higher.

Hızal, who was caught alongside Yıldız, performed similar tasks within the terrorist group.

In addition to orchestrating and monitoring escape plans and hosting fugitives in safe houses, Hızal, code-named "Yavuz," was the "person responsible" for FETÖ infiltrators within the Turkish Air Force Command.

He, too, had been a teacher until he was discharged from duty with a decree law.

Bora was a major within the Air Force until his discharge with a decree-law. He, too, had been convicted of being a member of an armed terrorist organization and providing shelter to fellow FETÖ members.

A court in Istanbul has arrested all three.

FETÖ has been under more intense scrutiny since the July 15, 2016, coup attempt its infiltrators in the army carried out, which left 251 people dead and thousands more injured.

Before that, the terrorist group was the perpetrator of two other coup attempts disguised as graft probes and was marked a security threat first in December 2013.

Prosecutors say that the group's infiltrators in law enforcement, the judiciary, bureaucracy and the military had waged a long-running campaign to topple the government. The group is also implicated in a string of cases related to its alleged plots to imprison its critics, money laundering, fraud and forgery.

The terrorist group faces operations almost daily as investigators still try to uncover their massive network of infiltrators everywhere – from military and police to judiciary and bureaucracy – but an unknown number of FETÖ members, mostly high-ranking figures, fled Türkiye when the coup attempt was thwarted.