A former music teacher at a Suffolk school has been jailed for five years for three indecent assaults on an 11-year-old pupil in the 1970s.
Derek Cable, 74, of Hastings, Sussex, assaulted his victim on three occasions during one-to-one lunchtime trombone lessons at Stowmarket Middle School.
On the third occasion the boy was made to perform a sexual act on Cable, Ipswich Crown Court was told.
The victim, now aged 50, was abused between 1975 and 1976.
Cable, who denied all the charges he faced, will remain on the sex offenders register for life, Judge John Devaux said.
In 2003 he was jailed for four years after being found guilty of sexually assaulting five boys in the 1970s and 1980s, when they were members of the Stowmarket Schools Concert Band.
He served two and a half years of that sentence in custody.
In the current case, the victim described how Cable had followed him into a storeroom on three occasions, indecently touching him and on one occasion forcing him to perform a sex act.
This had a profound effect on his life, causing him to take the "wrong path" through drinking, drug taking and crime, the court heard.
Judge Devaux said the offences represented a breach of trust and involved a child who had been considered vulnerable.