The trial of three Swiss teenagers accused of a brutal attack on five people during a school trip to Germany last summer, opened in Munich on Monday.
The alleged main offender was the only one willing to talk. The 17 year old responded to questions in court about himself and his life up to his arrest. The other teens remained silent.
According to highly publicised reports at the time, the youths, all from Zurich and all then aged 16, assaulted five men - selected more or less at random - in the space of 30 minutes. One of the victims was handicapped. Another was almost trampled to death.
The case sparked outrage in both Germany and Switzerland and the three now have to answer charges of attempted murder and intent to inflict grievous bodily harm.
Since the boys were minors at the time of the alleged offences, the hearing is being held in camera. Their parents are allowed to attend, but journalists are not.
The court rejected an appeal by the defence to move the trial to Switzerland.
A Swiss court could impose a maximum of four years on the accused if they are found guilty, while in Germany they face up to ten.
The trial is expected to last seven days. The court has invited 38 witnesses and three experts to give testimony.
swissinfo.ch and agencies