"It's like reliving it, " his mother Noreen Gosch said.

"But the bigger picture is, why are they doing this?"

The 12-year-old boy, from the affluent area of West Des Moines, Iowa, disappeared on 5 September 1982 after leaving for his paper route just before dawn.

When customers began complaining they had not received their papers, his father John went looking for him and found his wagon full of newspapers two blocks away. The police were contacted immediately and began a search that soon had the nation gripped.

From the start, Noreen Gosch was critical of the authorities, who she said were slow to react to Johnny's disappearance and inconsistent in their approach. Police turned up no evidence and no-one was arrested. As years went by, his became just another of the thousands of missing children cases in the US.

That was until 1999, when Noreen Gosch shocked the country by announcing that her son had visited her two years previously and said he had been forced into a decade of sex slavery.

According to Gosch, Johnny told his mother that, as his survival was a potential security breach, he was in hiding and would most likely never see her again.

Gosch has continued to assert that her son is alive and in hiding and that an international government conspiracy of satanists, paedophiles and pornographers is behind his disappearance.

Conspiracy theorists have since linked Gosch's disappearance to the case of Paul A Bonacci, who told lawyers in 1989 that he participated in Gosch's abduction and implicated other public figures in the sex ring.

In her book, Why Johnny Can't Come Home, published in 2000, Noreen Gosch revealed how she left the porch light on for her son for 11 years. After his visit in 1997, she turned it off.

"Johnny is now 36 years old, " she wrote on the website of the Johnny Gosch Foundation. "After years of suffering tremendous torture and pain at the hands of his captors, being used and abused, he and several others escaped. They have been hiding under new identities. They fear for their lives."

Last Friday, Gosch found two photographs on her doorstep. One showed her son on a bed, bound, gagged and wearing the clothes he had on when he disappeared. The second is of Johnny and two other children, also bound. Police are investigating who the other children could be.

This the not the only recent development in the case. Last January, White House reporter Jeff Gannon asked US president George Bush a series of factually incorrect questions about softball. People started asking questions and Gannon was revealed to be a former homosexual prostitute called 'Bulldog'. DNA tests are to be carried out to find out if he is Johnny Gosch, with some theorists suggesting he is the product of government training which uses sex to blackmail government officials.

Far-fetched it may be, but 24 years later this story looks set to run on and on.