A MAGISTRATE has slammed the behaviour of a former school principal found guilty of indecently assaulting a boy while working at Rokewood Primary School.Magistrate Jon Klestadt told Keith Rees he had breached a position of trust and committed a "serious" act of indecent assault."You were in a position of trust and you had a professional duty to act properly to (the victim)," Mr Klestadt said."There can be no greater betrayal of a young person than to be sexually abused by a person in a position of trust. "Young people need to be protected from this type of conduct."Rees, 58, of Ballarat, was convicted and sentenced to six months' jail, to be served by way of an intensive corrections order.He pleaded not guilty to four charges of indecent assault at Ballarat Magistrates Court on Wednesday but was found guilty of one count after a five-hour contest hearing.The court heard Rees assaulted a 13-year-old boy who would attend the school after hours to play computer games.The offending took place in 1985 when Rees was principal at the rural school.Defence lawyer Tom Dunos told the court Rees had specialised in physical education and taught adults through the sports commission.He said the matters before Rees had had an impact on his life and he had to leave the sports commission and resign from teaching.Three character witnesses each told the court Rees was an approachable and trustworthy person, and the accusations were out of character.Police prosecutor Leading Senior Constable Shaun Perry told the court there had been a long-term effect on the victim and Rees' trust had been violated.Mr Klestadt said while Rees had pleaded guilty to similar charges in the past, he was treating him as a first offender."You're entitled to be dealt with as a first offender because at the time of this offending you had not been charged with any offences until 2007," he said."I can't ignore that in 2007 you were dealt with for a series of like offences - one occurred at the same period of this offending."Meanwhile, a former Ballarat High School teacher facing 26 sexual assault charges briefly appeared at court before Magistrate Fiona Stewart.Michelle Lynn Dennis, 32, of Sebastopol, was charged with the offences in October last year. They include sexual penetration of a child under 16 years and indecent act with a child under 16 years.She will reappear in court for a committal hearing on June 17.