An İstanbul court on Sunday ordered the arrest pending trial of Emin Öner, owner of Ankara-based defense contractor Assan Group, and the company’s general manager Gürcan Okumuş in a case prosecutors describe as an “espionage” investigation tied to state security documents.
The two were detained on Wednesday as part of a probe run by the İstanbul Chief Public Prosecutor’s Office. Authorities also appointed Turkey’s Savings Deposit Insurance Fund (TMSF) as trustee over 10 companies operating under the Assan Group umbrella.
Prosecutors accuse Öner of membership in the faith-based Gülen movement, which Ankara designates as a terrorist organization but which is not recognized as such internationally, and of crimes involving state security documents. Okumuş is also accused of the latter. The court ruling did not include public details about which specific documents are at issue.
Assan denies wrongdoing. In a public statement the company said the files at the center of the case are its internal production and delivery schedules for 2025 through 2027 that were prepared at the request of the Turkish army. The company said these files remain in its records.
The investigation has also expanded outside the company. Last week İsmet Sayhan, the former chair of state weapons maker the Mechanical and Chemical Industry Corporation (MKE), was jailed on charges of unlawfully obtaining and misusing documents related to state security.
MKE is a state-run manufacturer that produces ammunition, artillery and other materiel for the Turkish Armed Forces.
Turkish media had reported claims that Turkish Armed Forces procurement plans were leaked to Assan.
Okumuş previously led Turkey’s Defense Industries Research and Development Institute (TÜBİTAK SAGE), from December 2018 until late 2023, before joining Assan as general manager in mid-2024.
Assan’s public profile has grown in the past year. The company showcased artillery shells and aircraft bombs built to NATO and Russian standards at the IDEX 2025 defense fair in Abu Dhabi in February.
Türk Kara Kuvvetleri Komutanı Orgeneral Selçuk Bayraktaroğlu, IDEF 2025 kapsamında standımızı ziyaret etti.
Sayın Komutanımıza, ürünlerimize ve yerli savunma sanayimize gösterdiği ilgi için teşekkür ederiz.
📍 Assan Group | 2. Salon – B06 Stand#IDEF2025 #AssanGroup… pic.twitter.com/8P0sRZpIP4
— ASSAN GROUP (@assan_group) July 24, 2025
Company accounts also show Foreign Minister Hakan Fidan and top military officers visiting its stand at the IDEF 2025 fair in İstanbul in July.
The trustee step puts Assan on a growing list of companies the state has taken under TMSF control since a failed coup in 2016. Government figures released in July said 784 companies with total assets valued at 42.3 billion lira at the time of the takeover were brought under TMSF management in the post-coup crackdown.
What comes next is a formal indictment and trial. Prosecutors said the investigation is continuing.
The Assan Group is an Ankara-based defense contractor founded in 1985 that says it exports to dozens of countries and supplies ammunition and bombs to both domestic and foreign buyers. Turkish media reported in May that authorities barred the company from public tenders for two years, a decision the company said it is contesting in court.