A former community centre manager has been found guilty of sexually abusing vulnerable children and adults in his care.

David Robertson, who was described by police as a highly manipulative man, carried out sexual assaults over a period of 37 years.

The 55-year-old went on trial two weeks ago facing 30 charges relating to lewd and libidinous behaviour and sexual assault.

Seven of his victims were children and the other nine were adults, including two men.

He was found guilty of 25 charges yesterday, including the rapes of two women and a six-year-old girl.

Judge Lord Boyd of Duncansby paid tribute to the victims for their courage in coming forward and giving evidence during the trial.

He said the court had seen the devastation Robertson had caused to so many lives and said he faced a significant jail sentence.

Relatives and friends of the victims packed the public gallery and gave jurors a round of applause after their verdict was read out to the court.

And following the hearing, the relative of one victim said: "The kids got their justice. He deserves what he gets. He is an animal – a paedophile."

The victims gave emotional accounts of Robertson's crimes when they gave evidence during the trial. One woman sobbed as she recalled how she had been raped as a young child, and the woman, now 35, said he had ruined her life.

She told the court Robertson would give her a choc ice as a treat to keep her quiet and said she did not really realise what he had been doing until she had grown up.

Another witness said letters were sent to the local council about his inappropriate behaviour more than three years before he was charged, expressing concerns about him inappropriately touching women at the community centre in the Heathryfold area of the city.

Yesterday, Aberdeen City Council said the information had been passed on to the appropriate authorities.

A council spokesman said: "Aberdeen City Council is com-mitted to protecting children and vulnerable adults and we treat any concerns about the care of children with the utmost of seriousness.

"The council was informed of a complaint about David Robertson, the (former) manager of Henry Rae Community Centre, in an anonymous letter in November 2007. Our records show that on receipt of this letter, the council informed both the police and Aberdeen Joint Child Protection Unit about the complaint."

The spokesman said Robertson was not employed by the council but had been appointed to his role by a voluntary management committee.

He added: "The council has strengthened the requirements for voluntary management committees as part of its new lease and management agreement for community centres."

Robertson accepted he had committed some of the offences when he gave evidence during his trial. He had offered to plead guilty to 14 of the charges last August but the offer was not accepted by the Crown.

He said he felt "disgusted" with himself and said he wanted to apologise to his victims, although he denied all of the rapes.

He cried as he said: "I was glad I was caught."

Robertson was remanded in custody for sentencing next month at the High Court in Glasgow.

Police Scotland Detective Inspector Janice Falconer said: "We welcome the conviction of David Robertson.

"He abused his position of trust and his conduct has blighted the lives of his victims. It is due to their courage that his abuse has come to an end and my thoughts, and those of my inquiry team, are with the victims and their families today."