Published in the face of police objections, it established that JonBenet Ramsey, a six-year-old beauty queen from Boulder, Colorado, had been strangled, but also supplied evidence suggesting she may have been the victim of a sado-masochistic ritual.
Although it was rumoured that JonBenet had been strangled, the report supplied a wealth of detail pointing to bondage: it said she was found on her back, with a cord round her neck that was attached to a piece of wood.
There was another cord around her chest and she was wearing a long white sequinned robe. She wore a bracelet inscribed with her name and the date of Christmas Day, 1996 - the day before her body was found - and had a small red heart inscribed on the palm of her left hand in red ink. Her skull had been fractured and she may have been sexually assaulted.
JonBenet was reported missing on Boxing Day after her mother, Patsy, found a note demanding $118,000 ransom. That evening her father, John, reported the discovery of her body in a basement room of the family home. While popular suspicion fell on one or other parent, no one has been arrested and no suspects named.
The case gripped America, partly because of JonBenet's celebrity, partly because her mother is an ex-beauty queen, partly because of the family's wealth and partly because the crime happened at Christmas. The murder also opened up the world of child beauty pageants to unflattering scrutiny. The post-mortem report was published as the result of a judge's order.
The police said details in the report could tip off the killer about lines of inquiry but journalists following the case noted that some details remained either unknown or undisclosed.
There was no estimated time of death - a crucial detail, in relation to the ransom note and in view of the fact that there was deep snow on the ground at the time and no footprints were found around the house. The question of whether JonBenet was sexually assaulted was also left open, although early reports - later retracted - said she was.
The police have been criticised not only for failing to find the killer but for their handling of the case, starting with what is described as the cardinal error of not searching or sealing off as soon as the presumed kidnap was reported.
The Ramseys, who have retained separate lawyers and insist they are innocent, have put it about that an aggrieved former employee of Mr Ramsey might have had a motive for the killing, and cite the specific sum in the ransom demand.
They have also taken out newspaper advertisements offering a reward for information that could lead to their daughter's killer.
The police have taken repeated handwriting samples from Mrs Ramsey and have also taken DNA samples from Mr Ramsey. The results, in both cases, are said to have been inconclusive. The only other person thought to be in the family house at the time, JonBenet's brother Burke, aged nine, was ruled out of the inquiry at an early stage.