It was a discovery startling, and disturbing, even by the standards of Afghanistan's anarchic violence.
Prisoners hanging upside down in a private prison, tortured by heavily armed soldiers of fortune seeking the millions of dollars in bounty offered by the Americans.
The arrest of Jack Idema and two companions after a shootout in Kabul gave a glimpse of a savage and largely unreported war taking place in the shadow of the Iraq conflict, and the assortment - mercenaries and misfits, fortune-seekers and fantasists - who have come to take part.
Idema, now in the custody of the notorious Afghan security chief, Baba Jan, in many ways epitomises these latter-day men who would be king in this part of the "Wild East".
His is a colourful background across three continents: author, adventurer and convict.
Some of us first met "Jack" in 2001, when the Taleban had retreated from Kabul, victorious Northern Alliance fighters were parading in the streets, and United States and British forces were pouring into Bagram airbase.
A dapper man in a black T-shirt and combat trousers, a Glock pistol strapped in his shoulder holster, Idema gave a graphic account of his supposed experiences as a former US Army Green Beret who had trained with the SAS and, as an adviser to the Tajik and Uzbek militias, had helped plan the operation to take the Afghan capital.
The meeting took place at the Mustafa Hotel, then being built in the city centre. It was another example of the seemingly endless carpetbagging opportunities then on offer.
The hotel's owners are a family of Afghan expatriates from New Jersey, the hotel named after one of three brothers.
Sipping whiskey, then retailing at US$140 ($213) a bottle at the Chelsi supermarket off Chicken St, Idema offered to organise a convoy to Tora Bora, where the Taleban and al Qaeda were making what was thought to be their last stand and where, the Americans were confident, Osama bin Laden was trapped.
After checking with the British military, some of us decided to decline his offer. Those who went were robbed at gunpoint a quarter of the way through the journey by their "guards" and made their way, bedraggled, back to Kabul.
Jack professed to be outraged. He would take the matter up immediately with his "good friends" General Quononi, the new Defence Minister, and Abdul Rashid Dostum, the warlord, and the bandits would be summarily executed.
After that Idema would regularly turn up at the Intercontinental Hotel, where most of the foreign journalists were staying, trying to sell videos and photographs purporting to show Taleban and al Qaeda terrorists training for assassinations and rehearsing gas attacks using dogs.
Some of these were bought for large sums of money, and one tape was shown on American network TV. But Idema later declared he was going to sue over alleged breach of contract, and also threatened to "punch out" Fox reporter Geraldo Rivera and a Fox TV presenter in a dispute over the recordings.
Idema had also taken legal action against the director Stephen Spielberg and his DreamWorks production company, accusing them of plagiarising a biographical book he had written, Red Bull Rising, in making a film, The Peacemaker, with George Clooney and Nicole Kidman. Idema, said to be demanding a US$130 million settlement, claimed Clooney's character, a special forces soldier who heroically prevents rogue Russian soldiers from exporting a nuclear warhead to Iran, was based on his own life in Lithuania, where he worked as an "undercover intelligence source".
His mission, undertaken on behalf of "private interests", was sabotaged by the CIA and FBI, he claims, because he was exposing deals with terrorists that embarrassed President Bill Clinton's attempts to improve relations with the Russians.
Idema has co-authored another book, Taskforce Dagger: the Hunt for bin Laden, with Robin Moore, who wrote The French Connection and The Happy Hooker, in which he develops his theme of playing a pivotal part in the fall of the Taleban.
The cover has a dramatic picture of him, bare-chested, semi-automatic rifle in his hand, flanked by two Afghan guerrillas.
But back in America Idema, known as Keith rather than Jack, was known for another type of combat - paintball. He ran a magazine called Paintball Planet and produced "combat helmets" for the game.
It was while running another company, Idema Combat Systems, which sold military clothing and equipment, that he was convicted in 1994 of swindling 60 companies out of US$200,000.
Sentencing Idema to three years' jail in federal prison, the judge ordered that he should undertake psychological tests.
Timothy Connolly, then an assistant secretary of defence at the Pentagon, appeared as a character witness for the defence. Records show Idema served with the 11th Special Forces Group as a "rigger", essentially a supporting role ensuring that equipment and supplies reached those in the frontline.
Whatever Idema's credentials are, the fact remains that he and others like him are common sights in Afghanistan. They have an eye for bounty, the top prize being the US$25 million ($38 million) offered by the US Government for bin Laden. There are also claims that some are involved in heroin trafficking - in the country that produces three-quarters of the world supply - and smuggling antiquities.
The Mustafa, now much expanded, is the favourite hangout in Kabul. Men in cropped hair, camouflage clothing and keffiyehs, packing guns, lounge in the Irish Bar, drinking bourbon with the Thai girls flown in to work at the hotel's new massage parlour.
Some operating in this murky world do indeed have official connections. David Passaro, a former Green Beret who arrived on a CIA security contract, is under arrest, accused of beating a 28-year-old Afghan detainee to death.
The war on terror is lavishly funded when it comes to bounties. The State Department is offering US$340 million for information leading to the capture or killing of 30 top suspects worldwide.
So far, US$56 million has been paid out internationally. Small wonder, then, that all kinds of adventurers are now buzzing round this honeypot.