Hanefi Avcı (born 1956, Kahramanmaraş Province) is a former chief of police in Turkey, and author of the best-selling book Haliç’te Yaşayan Simonlar, in which Avcı claimed that the Gülen movement had infiltrated the police and manipulated key trials such as the Ergenekon trials through judges and prosecutors close to the movement. Avcı, a conservative Islamist, was himself once close to the movement, and his children were educated in a Gülen school.[
Shortly after publishing the book, Avcı was arrested, accused of leaking information to the nominally Marxist-Leninist Devrimci Karargâh. Later he was additionally charged with being connected with the Ergenekon organization, in the odatv case.
In 2003 he was appointed head of the Police Department of Smuggling and Organised Crime. According to Avcı, he was too successful in this position, and as a result was moved to Police Chief of Edirne Province in 2005.
In 2010 he published the auto-biographical book Haliç’te Yaşayan Simonlar: Dün Devlet Bugün Cemaat, which covered various aspects of the "deep state" in Turkey, including the Ergenekon organization and the Gülen movement's infiltration of the police. Avcı's book claimed that the Gülen movement had highly placed people with privileged access to wire taps, and would publish information obtained this way when it suited it. He said he was one of those wire-tapped.
In September 2010 Avcı was arrested and accused of links with the terrorist group Devrimci Karargâh, which he denies, saying that he had "been expecting these kinds of defamations". He was accused of using a phone line belonging to Necdet Kılıç, an alleged Devrimci Karargâh member.
Hanefi Avci first convicted in 2013, but in 2014 began to be cleared of the alleged Ergenekon conspiracy charges
A criminal high court in Istanbul acquitted former police chief Hanefi Avci on Wednesday of charges of supporting a terror organization.