It sounds like something the CIA might have tried during the cold war: send an agent to bribe the cronies of an errant dictator, get them on board and slowly gain control of the foreign regime, while pulling the strings from afar. And if the spy gets caught, hope his torturers don't learn anything that can't be denied. It is not yet clear how much a 48-year-old man now in the custody of Zimbabwe's feared Central Intelligence Organisation (CIO) has told his interrogators, but since the news broke last week of his capture just before Christmas, he has confessed to working for South Africa's National Intelligence Agency. His job, according to Zimbabwean state media, was to hire top officials of the ruling Zanu-PF party, paying them up to US$10,000 a month in return for their allegiance and a steady flow of information about the inner workings of President Robert Mugabe's regime. So far, five senior members of Mr Mugabe's party have been arrested since the white agent's interrogation - a member of parliament, an ambassador, two senior office bearers and one of the country's wealthiest businessmen. All have been imprisoned on treason charges, a crime that carries the death penalty. Two cabinet ministers implicated in the incident are also awaiting a late-night knock on the door, according to reports. That the plot was hatched in Pretoria, and not Whitehall, Washington or even Canberra - eventualities Mr Mugabe has warned his followers to guard against - was what caught observers off guard. To date, South African President Thabo Mbeki has steadfastly defended Mr Mugabe. He has opposed sanctions, fought for him in the Commonwealth and laid out the red carpet when he and his officials drop in to buy luxury goods no longer available in their own starvation-wracked nation. Now it appears he was also planning for a future without Mr Mugabe. '[Mr Mbeki] was quietly studying the inner workings of Zanu-PF,' Zimbabwean constitutional law lecturer Lovemore Madhuku said. 'It has always been his intention to replace Mugabe without replacing Zanu-PF.' The foiled plot comes as a huge embarrassment to the National Intelligence Agency, not to mention the government. The agency has been basking in its recent success in exposing a scheme to overthrow the government of Equatorial Guinea. Intelligence Minister Ronnie Kasrils has refused to comment on the Zimbabwean venture, as has Mr Mbeki. Meanwhile, reports say the luckless agent is being interrogated and tortured. Once the CIO has finished with him he will likely be put on trial with the men he allegedly recruited. He will be able to count on little help from Pretoria.