Turkey kicked off on Tuesday the trial of some 500 people who were detained in raids in the authorities’ crackdown on alleged organizers of last year’s failed coup.

A total of 486 suspects will appear in a specially-designed courtroom outside Ankara, charged with crimes ranging from murder, violating the constitution and attempting to kill President Recep Tayyip Erdogan, state-run news agency Anadolu reported.

They are accused of running the coup bid from the Akinci air base northwest of the capital, which the authorities regard as the headquarters of the plotters where orders were sent out for fighter jets to bomb parliament.

The failed coup took place on July 15, 2016.

Almost all the suspects — a total of 461 individuals — are held in custody while seven are still on the run and the remainder charged but not in jail.

The main suspect, who will be tried in absentia, is exiled US-based cleric Fethullah Gulen. He is accused of being the mastermind of the coup, a charge he has repeatedly and categorically denied.

The trial is taking place in Turkey’s largest courtroom established inside a prison complex in Sincan to hear coup-related trials and has space for 1,558 people.

The courtroom has previously hosted mass trials related to the coup bid including one which opened in February of 330 suspects accused of murder or attempted murder.

And in May, 221 suspects were put on trial accused of being the ringleaders of the failed coup.

The attempted coup left 249 people dead, the Turkish presidency says, not including 24 coup-plotters killed on the night.

Anadolu reported there would be heavy security including 1,130 security personnel inside and outside the courtroom as well as snipers, armored security vehicles and a drone.

The trial is one of several held across Turkey judging coup suspects, in the largest legal process in the country’s modern history.