Detectives fear a paedophile who assaulted two young girls may have groomed other victims in the 30 years in between the two offences.
Slaughterman Graham Godbeer could be jailed indefinitely after he was found guilty of raping an eight-year-old girl in the early 1980s.
The jury at Exeter Crown Court convicted him without knowing that he had already admitted a sexual assault on a ten-year-old girl last year and a string of child pornography offences.
Messages found on Godbeer’s mobile phone suggest he was in contact with other child abusers and they suspect he may have abused more victims who have not yet come forward.
Godbeer, 55, of Veale Close, Hatherleigh, denied rape and three offences of indecency with a girl aged four to eight. He was cleared of two other rapes on the same victim.
He was found guilty and Judge John Neligan adjourned the case for reports and remanded Godbeer in custody.
He told him: "This has been a heartbreaking case. A need to see a report from a probation officer as to whether you pose a danger of causing significant harm to children.
"If that is the conclusion of the court your sentence will be indefinite. If not, it will be a lengthy prison sentence."
During a week-long trial the jury heard how he started grooming the child when she was just four and took her out in his car for ice creams before abusing her in a layby near Okehampton.
The victim, now an adult, told in a video recorded interview that his attacks caused so much pain she had difficulty walking.
He ensured her silence by telling her that nobody would believe her if she reported what he was doing and his attacks progressed from groping to full rape when she was just seven.
Godbeer denied any of the abuse happened and said he could not remember taking the girl out in his car on his own, although this was contradicted by his ex-wife.
After his conviction Mr Richard Crabb, prosecuting, told the jury that before the trial Godbeer had admitted the sexual assault of a child of ten and eight offences possession of indecent images of children.
Speaking outside the court, Detective Sergeant Rob Kingdom, from the Devon and Cornwall child protection unit, said the case was the most disturbing seen by several experienced officers.
He said the investigation started last year when a mother complained that Godbeer was grooming her ten-year-old daughter and started touching the child.
Officers found disturbing images and messages on Godbeer’s phone which convinced them he had a long-standing and predatory interest in the abuse of children.
They carried out inquiries into his background which resulted in the young victim of his early assaults coming forward.
DS Kingdom said: "We have identified very serious sexual offences over a number of years and we are very grateful to the victims for their bravery in coming forward.
“Our investigations are continuing with regard to him and to other people who he was in contact with. His text messages showed he was in touch with other like-minded people.
“One of the messages appeared to be inciting Godbeer to commit offences against children. He did not have a computer but had images on his mobile phone.
“We are really concerned about his lifestyle and activities. One of the images is of a child who we would like to be able to identify.
“He is quite a depraved character and we see him as a danger to children and to the vulnerable in general. We are really pleased with the verdict because it shows the victim has been believed.”