The Thai police soon announced they were holding a press conference where - initially at least - they said Karr would take centre stage to tell his tale.

About 100 members of the press from all corners of the world battled for space at the Thailand Immigration Department's detention centre and waited for the show to begin.

Karr came forward, but was placed away from the main table. He sat there and his hands began twitching. His eyes darted around the room.

Perhaps sensing that the star of the show was not going to keep his end of the bargain, the people in charge of the case - the chief of Thai immigration police General Suwat Tumrongsiskul and Ann Hurst, an official with the US Department of Homeland Security - took over.

They laughed, they cracked jokes with the media. And Karr looked on, forced to be, for the moment at least, part of the support cast in his own story.

But he was not to be denied. As he was led from the room, he chose his steps carefully, and offered up sound bites as he walked.

'I was with JonBenet when she died,' he said. Then he paused. Someone asked 'are you innocent?' 'No,' he replied.

When it was over, the talk on everyone's lips was that something was just not right. It was all too prepared - Karr looked like he knew exactly what he was doing all the way through, like it had been long prepared, like he knew how to play the press.

What the world then found out about John Mark Karr was this.

He grew up in the small town of Hamilton Alabama with his parents and two elder brothers.

He was married twice - first in 1984 to Quientana Shotts, when he was 19 and she was 13. The marriage was annulled in March 1985.

His second marriage was to 16-year-old Lara Marie Knutson in May 1989. He was 24 at the time. Their first two children - twin daughters - died soon after they were born on September 1, 1989, but they later had three more children. The couple were divorced on July 10, 2001.

Karr had been arrested before the divorce - in Petaluma, California, in April 2001 on five misdemeanour counts of possession of child pornography. He pleaded not guilty, he jumped bail and he had not really been seen in the US since.

Then he popped up in Bangkok. Then he said he was involved in JonBenet's death. And then the cracks in the story began to appear.

Over the next few days, stories seemed to change almost by the hour. Officers involved in the case backtracked regarding his confession. Claims that were made by Karr were denied.

Police General Suwat said Karr had told him he had drugged and sexually assaulted JonBenet before accidentally killing her. But the autopsy report found no evidence of drugs.

The immigration police chief then said Karr had claimed he had picked up JonBenet at school and taken her back to her home. But the murder happened during the Christmas vacation.

Then Karr's former wife, Lara Marie, spoke up and said she believed Karr was with her in Alabama during the Christmas break in 1996.

American investigators at first said Karr knew things about the JonBenet investigation that had not been released to the public. But they were unable to give answers when asked just what that information was.

And as the media dug around in Bangkok to find out more about the man, the contradictions piled up.

To people at the hotel where he was staying he was either a creep or a really nice guy. The only thing he really seemed to care about, they said, was whether or not his television could pick up CNN - a claim later repeated by his jailers, who said his only request from his cell was that he could watch that station.

To his employers and former colleagues, he was either a misunderstood man who simply cared for children, or just plain nasty.

What is certain is that Karr was very careful. He covered his tracks well.

Major Supachai Paladech, inspector in charge of deportation, said all Karr would say from his cell about his life was that he had made lots of money teaching in 'Europe and Central America' so did not need to work - even though he had sought and found employment at three of the Thai capital's international schools.

No one at those schools knew much about him - again he kept to himself. Bangkok Christian College assistant director Banchong Chompoowong said Karr was too strict, but not really much trouble. But parents said he was a menace to their children.

What did emerge before Karr was spirited away to the US, however, was that he had been undergoing cosmetic surgery. Three clinics confirmed this and then one - the Pratunam sex-change clinic - denied he had done so. So was he actually thinking of changing his sex? Or just preparing himself to face the world as the police noose tightened?

What is certain is that he was very particular about his appearance. As he left for the US - to face the DNA tests that would solve whether he was actually involved in JonBenet's death once and for all - Karr asked his captors specifically for a tie and a new shirt. He knew he would be travelling business class and again the cameras would have him in their focus.

Once he got to the US, however, the final threads of his story fell apart. Extradited from California to Colorado, the DNA tests failed to match anything found on JonBenet's clothes and he was thus sent back to California to answer the child pornography charges he had run away from in 2001.

Tellingly though, in the days since his return to the US, transcripts of his e-mails and phone calls to Professor Tracey have emerged on the internet. And they tell a bigger picture of a man who has deluded himself. Karr was thinking Hollywood - and his plans were lofty.

He spoke with Professor Tracey of film rights to a book they were planning about his 'involvement' in the JonBenet case, and of who he had picked for his own portrayal: 'I already know the actor I want to play my part. Johnny Depp. He reminds me so much of me. I have this film where he plays Willy Wonka. It's very similar to my personality except for the fact that Willy Wonka did not know how to treat children. He had no knowledge of how to be around children.'