A "respected office holder" in the Mormon church, from Cambridge, has been given a seven-year jail sentence after being convicted of raping and molesting a teenage boy he was "mentoring".
Postman Martyn Conway, 48, abused the boy for several years in the 1980s - once molesting him in a church, Cambridge Crown Court heard.
The youngster - now grown up - was left psychologically scarred and could not "steel himself" to complain until many years later, a judge said.
Conway, who is married and was planning to emigrate to Utah in the US, home of the Mormon church, was convicted of eight offences of sexual abuse following 13-day trial.
He had denied any offence.
Judge Anthony Bate said the Mormon faith did not tolerate homosexual activity but Conway had broken the code.
"You were driven by some compulsion to throw aside the strict Mormon code by which you professed to live," the judge told Conway.
"It was a prolonged campaign of sexual abuse."
In later years, the victim, who cannot be identified for legal reasons, had suffered mental health problems and attempted suicide, the court heard.
Conway, who delivered mail in Cambridge for more than 20 years, would remain on the sex offenders register for the rest of his life, the judge said.