Turkish prosecutors sought on Thursday aggravated life sentences for former Istanbul governor Hüseyin Avni Mutlu and former Istanbul police chief Hüseyin Çapkın for their alleged links with the Gülenist Terror Group (FETÖ).

Mutlu and Çapkın were among 15 former governors and district governors, who were previously detained as part of post-coup investigations over their alleged links to the terror group that staged the July 2016 defeated coup when 250 people were killed.

According to the indictment, the suspects are accused of "attempting to disrupt the constitutional order", "attempting to abolish the Turkish parliament and government by force and violence", and "being a member of an armed terror group."

Mutlu was also among those who were accused of financing the FETÖ.

When asked about the contact information of Akın Öztürk, the former air force commander accused of commanding the pro-coup troops, found on his phone, Mutlu said he probably encountered with Öztürk when he was the governor of southeastern Diyarbakır province. Back then, Öztürk was the commander of the Diyarbakır Main Jet Base.

Mutlu served as governor of Istanbul between 2010 and 2014, after which he took a post within the Interior Ministry as a civilian authority.

Prosecutors also asked the court to order for the arrest of another key suspect, Hüseyin Çapkın who was released after a brief detention over his FETÖ ties.

Çapkın was a part of the office security forces in Istanbul, which were criticized for their disproportionate use of force against the protesters during Gezi Park riots in 2013, which started as an environmental protest and later turned into nationwide anti-government riots.