Fikri Mehmet Karadağ is a retired Turkish army colonel who was indicted for treason in the Ergenekon investigation for allegedly heading ultra-nationalist organizations called the Association for the Union of Patriotic Forces (Turkish: Vatansever Kuvvetler Güç Birliği Hareketi), and the Kuvayı Milliye Derneği (National Forces Society).
It has been alleged that Karadağ is connected to the assassination of businessman Üzeyir Garih on the basis that the perpetrators knew or were subordinate to Karadağ. Garih was assassinated on 25 August 2001 by Yener Yermez, of the Hasdal barracks' café (Turkish: çay ocağı). Also working in the café was lieutenant Murat Oğuz, who got caught in 2001 for petty fraud with the Ergenekon investigation's key figure, Tuncay Güney. It is alleged that both Oğuz and Yermez were subordinate to Karadağ, in the capacity of Commander of the Mechanized Regiment (Turkish: Mekanize Alay Komutanı).
Ergenekon suspect Oktay Yıldırım (whose grenades in Ümraniye launched the investigation) was also stationed in the Hasdal barracks. Yıldırım was in the 6th Infantry Brigade (Turkish: Hasdal Kışlası 6. Piyade Tugayı) from August 1999 to April 2005.