The gunman who opened fire on the U.S. Embassy in Bosnia in October last year and his two accomplices will go on trial in Sarajevo on terrorism charges on Friday.

According to Bosnian prosecutors, Mevlid Jasarevic, Emrah Fojnica and Munib Ahmetspahic formed a terrorist group in the northeastern village of Gornja Maoca, home to adherents of the ultraconservative Wahhabi branch of Islam, with the goal “to improve the status of their community through violence and terrorist activities against state institutions and foreign diplomatic missions.”

The defendants, who have pleaded not guilty, may face up to 20 years in prison if convicted. Jasarevic has also been indicted in the United States on attempted murder, assault with deadly weapon, and destruction of property charges.

Bosnian prosecutors are planning to call on 38 witnesses and experts, and present about 100 pieces of evidence to prove the suspects’ involvement in the attack.

On October 28 last year, Jasarevic spent about 50 minutes firing on the U.S. embassy in downtown Sarajevo from a Kalashnikov assault rifle, striking the building with 105 bullets.

A security guard was seriously wounded in the attack, before Jasarevic was wounded by a police sniper in a shoot-out in front of the embassy and arrested.

The attack raised fears over the threat from radical Islam in the Balkans, where Muslims constitute 40% of the Bosnian population.