Thomas Osmond was jailed for seven years after being tracked by a detective who refused to believe he was dead.
Osmond, 46, left a suicide note in March 1995 on the day he was due to stand trial for sex offences.
He wrote that he had killed himself by jumping off a river bridge.
Osmond was seen standing on the bridge over an 80ft drop above the River Usk in Newport, Gwent.
He planned to copy the BBC TV character Reggie Perrin by faking his suicide but setting up life under a new identity.
But Detective Constable Ken Price never accepted Osmond had killed himself.
He spent three years on his trail and finally traced him to Bristol.
Father-of-three Osmond was living as a bachelor using the name Stephen Williams and working as a telesales clerk. DC Price arrested him as he was arriving for work.
He was at Newport Crown Court today to see Osmond jailed for what the judge described as "vile and wicked" offences.
The court heard that Osmond watched as a boy of 12 had sex with his wife Lesley, from whom he has since been divorced. Osmond also committed a sex offence against a boy of 14.
Peter Murphy, prosecuting, described Osmond as a "clever man", taking a master's degree in theology at Cardiff University at the time of the offences.
Osmond was jailed for six years for the sex offences and 12 months for breaking a condition of his previous bail.
After the case, DC Price, 51, said: "I was never fooled for a moment by the suicide note."Reuse content