Karr's admission collapses under even the slightest scrutiny. The first glaring discrepancy was highlighted by his ex-wife, who claims Karr was with her on the other side of the country during Christmas 1996, when JonBenet was murdered.

Lara Karr, through her lawyer, told reporters that she "sincerely believes there was no Christmasf anytime between 1989 and 2000 when they were divorced, when her husband was not with her and her family at Christmas time."

In addition, officials in Bangkok had said Ramsey told them that he had drugged her before sexually assaulting her. The child's autopsy reports, however, showed no drugs in her system. There was never any conclusive evidence about whether or not she was sexually assaulted.

Gruesome death Karr also claimed the child's death was an accident, but the six-year-old's body had been found strangled slowly with a rope that the killer had attached to what appeared to be the handle of a paint brush. She had also received a huge blow to the head. The autopsy report estimated the size of the wound at close to a foot long.

Nevertheless, US law enforcement officials insist that Karr is their man. One source told reporters in the US on Friday that Karr knew graphic details about the crime scene that had never been made public. The details, he said, were known only to the medical examiner that performed the autopsy and a small group of investigators working on the case.

By now, John Mark Karr . . .

who is expected to be extradited back to the US later this week . . . has taken on an infamy worthy of Lee Harvey Oswald in the US, with his background being pulled apart for analysis. The reporting and investigation of the story has reached almost hysterical levels.

Authorities are allegedly analysing whether an entry the 18-year-old Karr made in his school year book which said "maybe I shall be the conqueror and live in multiple peace" was relevant to the signature of 'S.B.T.C.' left at the end of the ransom note found near JonBenet's body in 1996.

As a young adult, Karr had had an abnormal if not abusive history with young girls.

In 1984, aged 19, he convinced a 13-year-old neighbour to cross the Alabama state line into Georgia and legally marry him. In February of the following year, the girl filed a complaint saying Karr had used tactics of "intimidation and fear" to get her to marry him and the marriage was annulled.

Karr married second wife Lara in 1989. She was just 15 at the time. The couple, who have three sons, divorced in 2000, around the time Karr was charged with five counts of possessing child pornography. Karr had spent most of the last decade working as a teacher. In autumn 1996, just months before JonBenet was murdered, he received a substitute teaching certificate and started working in Alabama.

Complaints made But by November that year, he had been removed from the roster by a supervisor because of complaints received about him being too affectionate with children. He returned to college studying early childhood education at the University of Alabama.

At some stage around this time, according to his brother, Karr began researching and writing a book about men who commit sexual crimes against young girls. Among the cases he was allegedly studying was JonBenet Ramsey's murder and a 1993 case of a child called Polly Klaas.

Klaas had been abducted from her parent's home near the wine country of Petaluma in California. She was later found dead.

In 2000, the Karr family decided to move to the San Francisco area, and they settled in Petaluma County where Klaas had been murdered. In April of the following year, the Napa County police alerted the school board that they were investigating Karr for five counts of possession of child pornography and he was taken off the roster. His wife had by now filed for divorce.

When Karr was charged and released on bond from jail in autumn that year, he left the country. For the next five years, he taught his way around the world, working in PAGermany, Holland and South Korea before arriving in Thailand, which he'd already visited several times in June of this year. He had begun teaching eight-year olds at an international school in Bangkok just the day before he was taken into custody.

Strange correspondence At some stage while overseas, he started communicating with Michael Tracey, a Colorado University professor who had been involved in documentaries about JonBenet Ramsey's death. Over the course of four years, he and Karr allegedly exchanged hundreds of emails, the content of some causing Tracey to suspect that Karr could have been involved in her death.

Tracey eventually alerted authorities to the correspondence, some of which has already made its way into the US media, sparking further criticism of the investigation.

In one such email, Karr asked Tracey to go to the Ramsey's old house at Christmas time and read out the following ode: 'JonBenet, my love, my life, I love you and shall forever love you. I pray that you can hear my voice calling out to you from my darknessf We shall meet again and laugh together once more as we did in this life. If there is to be a life for me after this one I pray it will be with you . . . together forever with you and other little girls who are gone now from my life forever. This would be my heavenf" His hell would be that nobody will believe he killed JonBenet. This weekend, that fear looks like being realised.