A court in Ankara on Tuesday sentenced five people to life in prison over their role in the 2016 assassination of Russia’s ambassador to Turkey, state news agency Anadolu reports.

The five were handed aggravated life sentences for attempting to overthrow the constitution and premeditated murder.

Three of them, accused of helping the shooter commit the assassination, were separately charged with terrorism ties.

Aggravated life sentences are the harshest terms possible in Turkey, ever since it abolished the death penalty in 2002.

Eight others were sentenced to jail terms ranging between three years and up to more than 10 years.

Ambassador Andrei Karlov was shot dead by off-duty policeman Mevlut Mert Altintas on December 19, 2016, at an exhibition in Ankara.

The shooter shouted Islamist slogans and denounced Russia’s involvement in the Syrian conflict before being killed by police.

An indictment had concluded that U.S.-based Islamic cleric Fethullah Gulen and his network, which Ankara blames for a 2016 failed coup attempt, premeditated Karlov’s murder.

Turkey designates Gulen’s group as a terrorist organisation; the cleric denies the charges.

In total, 28 suspects, including Gulen, were on trial.

The court delayed the trial of nine suspects, including Gulen, while six other defendants were acquitted of all charges, according to Anadolu.