42 out of 78 former Bank Asya managers were detained Friday for providing financial assistance to the Gulenist Terror Group (FETO), as part of an ongoing investigation.

The Organized Crime, Smuggling and Financial Crime Bureau of the Istanbul Public Prosecutor's Office is investigating 87 former top-level directors, general managers and assistant managers who worked at Bank Asya from the end of 2014 until the bank's assets were handed to the Savings Deposit Insurance Fund (TMSF) in May 2015. The prosecutor then issued a decision to take 78 of the suspects into police custody.

The 87 suspects are under investigation for "membership of a terror organization" and "providing financial support to a terror organization."

An operation by the Istanbul Financial Crime Branch Directorate took 42 of the suspects into custody in an operation that spanned seven provinces. Police are also searching the suspects' addresses for further evidence.

Five of the total 78 suspects are already in prison for other offenses, while police are working to locate the remaining 31 suspects.

On May 29, 2015, Turkey's banking watchdog ruled for the complete TMSF takeover of all shares of Bank Asya, which was believed to be the main financial institution for FETO and affiliated companies, due to the bank's failure to fulfill its obligations under the scope of Article 70 of the Banking Law that regulates the Banking Regulation and Supervision Agency's (BDDK) intervention in troubled banks. The BDDK added that the trouble in Bank Asya's financial structure, its maladministration and operations pose risks to depositors as well as to the security and stability of the financial system.

Ankara accuses FETO of being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.

This campaign culminated in the July 15 coup attempt, which saw 250 people killed and 2,200 wounded.

In the wake of the coup attempt, tens of thousands of FETO suspects have been arrested, including many in the armed forces, police, the judicial system, and education and business sectors.