The new evidence has shattered the complacency of the authorities in the town of Wenatchee, in the heart of Washington state, who had been congratulating themselves oncracking what they believed to be the largest child sex conspiracy in American history.
The foster father is none other than Robert Perez, the detective who headed the Wenatchee police department's child crime unit between January 1994 and the end of last year. During this period, 45 Wenatchee residents, 21 of them women, were charged with sexually abusing minors. They were accused, in large part on the evidence supplied by the girl living in Mr Perez's home, of engaging in oral sex and sexual intercouse with their own and other people's children. Two dozen girls and boys had allegedly been involved. Of those charged, 26 were found guilty and given combined sentences of more than 300 years.
Mr Perez became a local hero, celebrated by the press, business leaders and elected town officials. Yet, in what appears to have been one of many curious oversights by the Wenatchee establishment, he was found last year to have used undue physical force against his foster child and star witness.
The girl, who for legal reasons must be known only as M E, was transferred at the end of last year to another foster home after a number of violent run-ins with Mr Perez, who admitted that once he twisted her arm.
Last month M E ran away to her grandmother's house. Almost the first thing she did was make a phone call to Robert Roberson, a Pentecostal church minister who was acquitted at the end of last year on four counts of child rape, having endured 135 days in jail. M E was a key witness against him.
Pastor Roberson says that the child begged his forgiveness for lying about his participation in, among other things, ritual sex orgies at the altar of his church, "the House of Prayer". Later, in the presence of his lawyer, Mr Roberson videotaped an hour-long conversation with M E. "I had to make it all up," she said on the tape. "Bob Perez was there and he pressured me to say it." The pastor, interviewed by telephone, said he had asked M E how she came up with such bizarre stories. "She told me, 'I thought if I made them really bizarre, Pastor Robbie, nobody would believe them.' "
The reason why Mr Roberson himself was charged, he believes, was that he had been over-vigorous in a crusade to expose Mr Perez as a fraud and get M E's parents, Harold and Idella Everett, out of jail. Armed now with M E's recantation, the pastor has persuaded lawyers to lodge an appeal against the Everetts' convictions.
That may only be the beginning of a legal counter-assault against Mr Perez and the Wenatchee town authorities, who are facing damage claims of $100m from 14 of those prosecuted on charges of paedophilia. Pressure is also mounting from Washington state congressmen and civic groups for a full-scale inquiry.
The curious thing is that Pastor Roberson and other concerned citizens have had to wait so long for public pressure to build up. M E is not the first child witness to recant. Two girls interviewed last year by the Independent on Sunday said they had been intimidated by Mr Perez into telling lurid lies.
Another disturbing element in the Wenatchee affair is that virtually all the defendants who hired private counsel were acquitted, while most of those obliged to rely on public defenders were found guilty. In ahigh number of cases, those imprisoned were found to be both extremely poor and unusually ill-educated. Idella Everett, who has an IQ of 58, was charged on 1,586 counts of child rape.
As for Mr Perez, whatever the future may hold he will always be able to savour past glories. In 1995 he was voted Wenatchee's "Foster Parent of the Year". In March this year the mayor of Wenatchee instituted a new award for civic responsibility. In recognition of Mr Perez's achievements, the mayor named him "employee of the month".