The trial has begun in canton Valais of a man accused of sexually abusing around 50 girls, including three who were drugged and assaulted in a school dormitory.
The accused appeared in court in Brig to answer charges on Monday. The offences, which include rape, took place over 11 years, notably in cantons Vaud and Valais. Many of the victims were under 16.
In the most high profile cases in 2000, three girls were drugged with a chloroform-like substance and assaulted in a dormitory at Aiglon College, a private English style boarding school in Valais. The Duke and Duchess of York decided against sending one of their daughters to the school after the attacks.
DNA analysis of traces of semen found on the scene were used to identify a man seven years later. The man, who is aged in his 60s, was arrested at his home in Olten, northern Switzerland.
Other schoolgirls were also assaulted after being drugged while sleeping in a holiday hostel in Fiesch, Valais in 1996.
The man previously served a ten-year prison term for repeated indecent assault of children and underwent psychiatric treatment.
swissinfo.ch and agencies