A shamed ex-soldier who claimed his rape of a widow in Northampton was "consensual" heaped untold distress on an aging family by dragging them through a trial, a lead detective has said.
The serial offender was just 18 and serving in the army in 1986 when he carried out the brutal sex attack in Northampton.
Speaking after the guilty verdict was pronounced yesterday, lead investigator in the case, DS Julie Gallagher, said the rape had a lasting effect on the victim - a widow, who had only just lost her husband.
But Vernon's claim that the attack was a consensual sexual act then further heaped misery on the woman's family, by forcing them through the ordeal of a week-long trial
DS Gallagher said: "It was incredibly distressing - the victim had recently been widowed.
"To deny the offences and then say the victim was in a one night stand was very hard for the family.
"One man was an 89-year-old that had to give evidence. It was horrific for him and it could have been avoided."
At about 3am on October 11, 1986, Vernon, wearing a ski mask, had broken into the Eastfield home of his 68-year-old victim.
He stole little more than £20 from the bedroom of his victim before then raping her at knifepoint.
But having fled the scene - he was then embarked on a 31-year spree of offending.
In 2015, he and Mirriam Nabi, 28, of Beckets View, Northampton, carried out a brutal robbery at the One Stop Shop in Hillgrounds, Kempston in which he repeatedly kicked the face of the shopkeeper.
In 2016, the rape case was re-opened by the Northamptonshire Police Cold Case team as part of a regional review of unsolved rapes and murders dating back decades and detectives interviewed witnesses from as far away as America and Scotland.
As part of the original investigation, blood group samples were taken from potential suspects as a means of elimination.
But DNA-matching techniques were not introduced until the 1990s and there have since been a number of advancements in forensic science technology.
Semen, which had been found on the nightdress and bedding of the victim following the rape, were forensically re-examined and a DNA match was made linking Vernon to that rape.
Vernon, who is currently serving an 18-year sentence for armed robbery, was charged in 2017 with the rape he committed in Northampton as an 18-year-old.
The guilty verdict yesterday afternoon ends a 31-and-a-half year battle for justice by the victim's family.
DS Gallagher said: "I hope that this verdict will bring the family some comfort, knowing that the man who committed this crime has finally been brought to justice.
“The cold case team will continue to investigate undetected rapes and homicides and continue to bring offenders to justice.”