An Istanbul court on Friday handed down prison terms between eight to ten years to former columnists for Zaman, the now-defunct mouthpiece of the Gülenist Terror Group (FETÖ).

According to the final verdict of the 13th Heavy Penal Court in Istanbul, columnists Ali Bulaç and Şahin Alpay were sentenced to eight years while Mümtazer Türköne and former Ankara bureau chief Mustafa Ünal were handed down ten-year prison terms each for membership of a terrorist group.

Ahmet Turan Alkan and İbrahim Karayeğen were released from detention while five other defendants were acquitted of terror charges.

Prosecutors had asked earlier for aggravated life sentence for suspects who were detained in 2016 after a coup attempt by military infiltrators of FETÖ that killed 250 people.

FETÖ, led by fugitive Fetullah Gülen, infiltrated state institutions over decades, starting from the 1970s. By the 2000s, it had come to dominate many state institutions, especially the judiciary, police and the military, which it used for its own nefarious purposes.

The terrorist group, which faces a new barrage of trials after the July 15, 2016 coup attempt, is accused of running media outlets to vindicate its actions and orchestrating defamation campaigns against the group's critics.

The terrorist group once wielded considerable clout in the media where it ran a broadcaster. The group owned several TV stations, published newspapers and magazines that disseminated the group's propaganda and had several radio stations. Most were closed down as part of the crackdown on FETÖ and were handed to trustees as the legal process against FETÖ members got underway. The media was key for Gülen to spread his messages to his followers.

Gülen, who faces extradition from the U.S., is already implicated in a string of criminal cases including those on the coup attempt carried out by his followers in the military, and sham trials against his critics. Since December 2013, when FETÖ emerged as the perpetrator of two coup attempts, FETÖ has been regarded as a security threat.

Many executives of FETÖ-linked media, including Zaman's editor-in-chief Ekrem Dumanlı, remain fugitives. Dumanlı was last spotted in the United States where Fetullah Gülen resides.

The Zaman daily, considered the flagship media organization of the FETÖ, was shut down after trustees were appointed to the newspaper by court shortly before the coup attempt in 2016.

In February, an Istanbul court handed aggravated life sentences to six defendants including journalists and writers Nazlı Ilıcak, Mehmet Altan and his brother Ahmet. They were accused of serving as the media arm of FETÖ.