Libya: Muammar Gaddafi's secrets finally revealed
Since Muammar Gaddafi's ignominious death at the hands of a rebel mob in October 2011 much has been written and said about him. But now a new film, with unprecedented access to those close to Gaddafi, provides a comprehensive study of Libya's brutal and contradictory long-time leader.
Ali Aujali, Gaddafi's former ambassador to the United States, is an exceptionally charming man.
He is also something of a magician. He began his career in the Libyan diplomatic service a couple of years after Gaddafi seized power in 1969.
In a series of postings from London to Latin America, he explained away the excesses of the Gaddafi regime. So I was rather surprised to sit with Mr Aujali surrounded by the staggeringly ornate Libyan embassy in Washington and hear him tear the colonel to pieces.
Mr Aujali defected to the rebels in February 2011 and became their ambassador to the United States.
According to him, there was literally nothing good about the man whose regime he had served most of his adult life.
Secret after secret spilled out. We checked as many of his claims as we could.
There were anecdotes we could not follow up, such as his claim that a young man had been tied to two cars and ripped in half after complaining that Gaddafi had had sex with his wife.
But there were other claims we could check.
One was that on 22 December 1992, almost four years to the day after Pan Am 103 was blown up over Lockerbie, a Libyan Arab Airlines 727 was shot down on Gaddafi's orders.
A total of 157 people - Libyans and foreigners - had died.
Its flight number, curiously, was 1103.
After Gaddafi fell, the British wife of one of the victims tried to get the new Libyan government to open an enquiry.
Reporters pieced together statements made by pilots of military jets in the area, air traffic controllers and airline employees.
But what was important about Mr Aujali's statement to us was that it was the first time a true insider had spoken out.
Was he sure? "100%," he said.
A bomb with a timer had been placed on board the plane. When it failed to detonate, Gaddafi ordered the plane to be knocked out of the sky, near Tripoli airport.
Mr Aujali said his motive had been to show the West - via Libya's state-controlled media - how international sanctions imposed after Lockerbie were hurting ordinary Libyans.
Unable to buy spare parts, the story went, Libyan Arab Airlines could not fly its planes safely. The dead were victims of what Gaddafi liked to represent to visitors as Western terrorism.
The official explanation varied. Eventually the regime jailed the pilot of a Libyan Air Force MiG and his instructor, claiming they had collided with the plane.
The instructor, Majid Tayari, agreed to meet us in a Tripoli hotel. There was no collision, he insisted. He saw part of the tail of the 727 hurtling towards him.
Something hit the MiG from underneath, then fire broke out. Both pilots ejected. According to him the 727 had been hit first.
Pieces of fuselage rained down at very high speed and punctured the skin of the MiG.
Libyan Arab Airlines' air safety manager in 1992, Mahmud Tekalli, also disputes that a mid-air collision was the cause. He believes flight 1103 was deliberately destroyed.
We went to the crash site and then negotiated our way past the militia guarding Tripoli airport.
A back road runs past elderly planes.
Off the road we found the wreckage of Flight 1103 in eerily good condition, protected by the desert climate, ready to lay bare its secrets to crash investigators.
Mr Aujali was not the only insider we met on our travels.
On a private island in the Pacific Ocean, we talked to Lutz Kayser, a German rocket designer who worked for Gaddafi in the 1980s.
Mr Kayser says: "He was a very nice, modest person and I had the impression he was hiding his weakness behind a facade."
Mr Kayser's wife, Susanne, says Gaddafi was "charming and could charm the birds out of the trees" but she said he later became disillusioned when he failed to set up a "utopia" in Libya.
In Havana we interviewed Frank Terpil, an American fugitive from justice who ran a "Murder Incorporated" operation for Gaddafi in the 1970s, killing Libyan dissidents abroad.
Mr Terpil said: "Gaddafi thought that anybody who was a dissident was going to be eliminated. He had contracts out on a bunch of people in London."
And after pursuing him for months, we finally reached Urs Tinner, a Swiss engineer who worked for Abdul Qadeer Khan, once called the most dangerous man in the world.
Mr Khan developed nuclear weapons for Pakistan and later offered nuclear technology to any country with the money to pay. Gaddafi was his most lucrative client.
Mr Tinner says he was not aware Mr Khan was a "nuclear proliferator" but when he realised he tipped off the CIA, who intercepted a ship with final parts for a centrifuge.
We also unearthed evidence of Gaddafi's sexual abuse of young girls.
And one of his female bodyguards, who now lives in hiding, told us she ended up fearing him: "[One night] we were going to witness the execution of 17 students. They did not hang them. They shot them. We were forbidden to scream. We were ordered to cheer."
Finally we found Gary Peters, an Australian bodyguard for the Gaddafi family, who had fled to Niger with the ex-leader's son Saadi, while Gaddafi made his last stand in Sirte. He said: "He stood to the last because he thought he could possibly reclaim his status."
Watch Mad Dog: Gaddafi's Secret World on BBC Four on Monday 3 February at 22:00 GMT or catch it later on catch it later on the BBC iPlayer.