A former Istanbul governor on Wednesday began serving an over three-year prison sentence for helping FETO, the terror group behind the defeated 2016 coup in Turkey.

Axar.az reports citing AA that after a court in Istanbul upheld Huseyin Avni Mutlu's prison sentence for knowingly and willfully aiding the Fetullah Terrorist Organization (FETO), he began serving his sentence in the northwestern province of Edirne, said the sources, who asked not to be named due to restrictions on speaking to the media.

Alongside his lawyers, Mutlu came to the Edirne courthouse to surrender, and after procedures at the prosecutor's office, Mutlu was taken to the prison.

On Feb. 9, the 30th Heavy Criminal Court in Istanbul sentenced Mutlu to prison in a trial on FETO’s infiltration of the civil service.

FETO and its U.S.-based leader Fetullah Gulen orchestrated the defeated coup of July 15, 2016, which left 251 people martyred and nearly 2,200 injured.

Ankara also 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.