A paedophile from Telford allegedly made a deathbed confession that Madeleine McCann was kidnapped to order.
Raymond Hewlett, who was a suspect in the case, reportedly wrote to his son, Wayne, who lives in Telford, with details.
Hewlett, who died from throat cancer in April, aged 62, had persistently refused to meet detectives investigating the disappearance of Madeleine from the McCann's holiday flat in Praia da Luz in May 2007.
He had been a suspect in the case because of his long record of rape and abduction of children.
His letter to his son, a builder, was delivered by an intermediary and is believed to have caused Wayne so much shock that he burned it.
Wayne reportedly said: "It was a bolt from the blue and I shook when I read it.
"He said he had had nothing to do with taking Madie but did know who had. He said a very good gipsy friend he had in Portugal had got drunk and 'let it out' that he had stolen Maddie to order as part of a gang.
"My dad said this gang had been operating for a long time and had snatched children before for couples who couldn't have children of their own.
"Maddie had been targeted. They took photos of children and sent them to the people they were acting for. And they said Yes or No.
"Dad said the man told him it was nothing to do with snatching children for a paedophile gang or for a sexual reason
"He said there were huge sums of money involved. And he totally believed what this man was saying.
"I actually burned it (the letter) because it unnerved me so much. To have a letter from someone you hated for so long was just mind-blowing. I couldn't deal with it."
The account fits with other theories regarding Maddie's disappearance, with witnesses saying several strange men were seen taking photographs of children around the Ocean Club resort prior to her disappearance.
Wayne added: "I can't believe he'd go to those lengths to make up some elaborate lie when he was so weak and ill."
By Andy Richardson