(Press tv) -- Aine Davis, who brutalized and beheaded western hostages in Syria, had been arrested near the Turkish city of Istanbul in 2015.

Officials in the Turkish court of Silivri found him guilty on Tuesday, further arguing that the 33-year-old had been plotting to carry out terror attacks in the country.

“I want to make clear I am innocent of the charges. I don’t even know why this case has taken so long to judge. I just want my freedom,” Davis said before the verdict was read.

The former driver and drug dealer from west London went to Syria in 2013 and three years later became a member of a 4-man group dubbed “The Beatles,” which reportedly holds more than a dozen foreign hostages.

Davis was named in 2016 as an accomplice of three other British nationals—Mohammed Emwazi, also known as Jihadi John, Alexanda Kotey and El Shafee Elsheikh

Davis, the only one of the group to face a trial, has denied all the charges.

US security services believe the terrorist group was behind the execution videos of British hostages Alan Henning and David Haines as well as American hostages James Foley, Steven Sotloff and Peter Kassig.

"He should face justice wherever it is. It doesn't matter if it's in England or Turkey or wherever. He should be in jail forever, " said Javier Espinosa, a Spanish journalist and one of the group's former captives.

In 2014, a British court gave a jail sentence to Davis’ wife, 27-year-old Amal el-Wahabi, who was found guilty of attempting to pay a smuggler to take $19,500 in cash to Davis in Syria.

With members from several Western countries, the ISIL terrorist group controls parts of Syria and Iraq, and has been carrying out horrific acts of violence, such as public decapitations and crucifixions, against all communities including Shias, Sunnis, Kurds, and Christians.

British authorities say that at least 800 UK nationals have traveled to Syria and Iraq to fight alongside various Takfiri groups, regarding them as potential security threats upon returning to the country.

Last February, the European Union's criminal intelligence agency Europol said up to 5,000 trained members of Daesh were at large in Europe, adding that some 30,000 militants from over 100 countries have reportedly traveled to Syria and Iraq since 2011 to join the ranks of Takfiri terrorist groups.