Prosecutors asked for a prison term of up to 15 years for Erdem Semih Yıldız, a lawyer for a defendant in the case of the assassination of a Russian ambassador in Turkey, over his links to the Gülenist Terror Group (FETÖ).

Yıldız faces charges of membership of a terrorist group. He was defending Salih Yılmaz, one of the defendants in the case, for the 2016 assassination of Andrey Karlov.

Karlov was murdered in an art gallery in the capital Ankara on Dec. 19, 2016 by an off-duty police officer associated with the terrorist group. The officer, Mevlüt Mert Altıntaş, was killed in a shootout with police, while several FETÖ figures were arrested following the assassination, including Salih Yılmaz. Yılmaz was a key figure in FETÖ's secret network in law enforcement and was accused of relaying instructions for the murder to Şahin Söğüt, the terrorist group's handler for Altıntaş.

Yıldız was found to be a user of ByLock, an encrypted messaging app exclusively used by FETÖ members, and faced a probe when he went on the run. Police detained him in Ankara while he was planning to flee abroad. Security sources say he had intimate ties with the terrorist group apart from ByLock use, including a stay in FETÖ's dormitories for university students while he was studying law. Authorities also uncovered his messages to a fellow FETÖ member who fled abroad in February 2019. Yıldız had said he would leave Turkey "as soon as possible," citing an investigation against him. He was also in touch with Selim Biçer, a member of the terrorist group organizing an "escape" to Greece for wanted members of the group.

FETÖ leader Fetullah Gülen and seven other individuals linked to the group are the prime suspects in the Karlov case.

The indictment includes digital evidence showing Altıntaş's connections to FETÖ. The evidence shows that Şahin Söğüt met Altıntaş 10 days before the assassination and on the same day, Altıntaş did online research about Russia. Prosecutors said in the indictment that Altıntaş originally planned to kill Karlov at a dinner for ambassadors hosted by the Justice and Development Party (AK Party) on June 27, 2016, but scrapped the plan when Karlov did not attend and went on a trip abroad instead.

They added that FETÖ and "foreign powers that used the group" aimed to derail bilateral relations between Turkey and Russia through the assassination and "drive the countries into a possible conflict" as well as "create chaos ahead of July 15, 2016."

The assassination came at a time of thaw in strained Turkish and Russian relations. Since the murder, Ankara and Moscow have gradually made progress in rebuilding their ties, which were disrupted by the 2015 downing of a Russian fighter jet over the Syrian border by the Turkish military.