A former teacher at one of Scotland's top private schools was yesterday imprisoned for eight months after admitting he sexually abused pupils in his care.

Jonathan Quick, a retired Latin and sports teacher at Dollar Academy, abused three boys and a girl and assaulted a fourth boy in the late 1970s and early 80s.

Investigations began into the teacher in 2002 after the suicide of 23-year-old David Young, a medical student who had been taught by Quick in the 1990s.

The final-year medical student at Aberdeen University had told his flatmates he was visiting a friend in Dundee. Instead, he went to Cebu in the Philippines, where he worked in an orphanage in his gap year.

He did not return to the orphanage but checked into a hotel and wrote a suicide note to his family - explaining he felt trapped and confused.

It was not until three months later, in June 2002, that they discovered he had been sexually abused by a teacher at Dollar Academy in 1990 in psychiatric reports that cite the abuse as the main reason for his depression and subsequent death.

David had told his parents he could not go on with his course, despite doing better than expected in his exams. They had no idea of the real reasons behind his decision.

"The Philippines was one of the last places he felt really happy and the police explained to us that those who commit suicide often choose somewhere they felt peaceful to go and die," Noreen Young, David's mother, told The Herald.

"I just couldn't understand how he had died in a hotel in the Philippines when we thought he was in Dundee.

"It was not until June that we discovered that he had been sexually abused by Jonathan Quick. We called the rector at the school."

Mrs Young and her husband John, a local GP, met the rector and chair of the board of governors who told them that there was no record of Quick abusing any pupils.

On their lawyer's advice, they contacted the police in August 2002 explaining that a criminal act had been committed. Officers interviewed David's friends, and in January 2003 interviewed Quick in the Rumbling Bridge nursing home where he lived.

"After months and months we were told that the procurators-fiscal had closed the case," said Mrs Young. "The police were not that interested and said there was no corroboration and that because David was dead they could not take it forward."

Dr and Mrs Young contacted Les Brown, a former detective with Strathclyde Police, who had helped a number of families who had suffered miscarriages of justice.

Mr Brown tracked down 500 former pupils who had been taught by Quick. Eight said they had been abused by Quick in different ways and a report was sent to the police with their statements.

"If it were not for Les we would have got nowhere," said Mrs Young. "We now know that Quick was removed from the boarding house after one boy made a complaint against him.

"We still don't understand why or how there was no record of that. We just can't comprehend how the school could have kept him on as a teacher.

"That was in 1981. David and many of the other pupils were abused after that. It is heartbreaking to know there are other victims and to hear that others are suffering now as a result of what Quick did."

Other former pupils told The Herald of their feelings of guilt and anger about the abuse they suffered. All were relieved that he pled guilty, but last night Mrs Young said she feared the short prison sentence given to Quick "sent out the wrong message to others".

She said: "The length of the sentence does not reflect the serious nature of his crimes. What message does this send out to other paedophiles?"

Quick's defence advocate said Quick was mentally and physically unwell and was keen to make amends by offering a financial donation to a children's charity. However, Sheriff David Mackie said there was no medical reason for him to be in a wheelchair. He gave him a custodial sentence and placed him on the Sex Offenders' Register.

"The offences to which you have pled guilty betray an appalling breach of trust in your position as a respected teacher of classics, sports and other activities. It is a form of offending which elicits the strongest feelings of abhorrence and repugnance.

"Worst of all, your offending has caused harm to your victims impossible to calculate, more profound and more pervasive than any physical injury."

Quick, 71, retired from Dollar Academy in 1995 when he was aged 60.