Castro, a former political reporter and columnist in Los Angeles, did not merely embellish the views of the characters he used to back up his stories about Hollywood celebrities. He invented his sources, arranged for them to be paid through mail-box addresses, and pocketed the money himself.
According to prosecutors, the 45-year-old Beverly Hills journalist operated an elaborate fraud for four years, selling suspect stories to American supermarket tabloid newspapers. He and his wife netted some dollars 214,000 ( pounds 141,000) before they were rumbled.
The subjects of his fevered typewriter included Elizabeth Taylor, Madonna and Earvin 'Magic' Johnson, the basketball superstar who retired after revealing he was HIV-positive. But Castro's final undoing was brought about by the Hollywood hard man himself: Clint Eastwood.
Mr Eastwood, the Oscar-winning director of Unforgiven, testified in court that he had taken to carrying a pistol after the Globe ran a phoney story saying that the Aryan Nation, a neo-Nazi group, had put a dollars 100,000 price on his head because he refused an invitation to address them. The story was accompanied by a photograph of the actor in the sights of a rifle.
Eastwood sued the paper and accepted an out- of-court settlement, but in the process Castro's scheme was uncovered. After pleading guilty to mail and tax fraud, Castro was jailed for five months, and he and his 31-year-old wife Renee were given five months' 'home confinement'.
While Castro contemplates the error of his ways from behind bars, America's tabloid editors are sitting nervously in their upholstered chairs. Sentencing Castro, US District Judge James Ideman said he imposed the lightest possible punishment because the tabloids wanted to print the Castros' dodgy stories. 'The publishers were well aware that their sources could be phoney,' he said.
As one (unpaid) reliable source told the Independent: 'The tabloids got a bit of a fright. They have to be much more careful these days.'