Davor Banic entered the prison compound in a car accompanied by his brother shortly before noon on Tuesday and was escorted by judicial police to the detention unit.
Banic is one of the five accused who have been on the run since October 11 this year when the Supreme Court issued a detention order for the accused. Three accused were remanded in custody while warrants were issued on October 26 for the arrest of the others.
Banic reportedly returned home from abroad on Monday evening, unobstructed despite the warrant for his arrest.