Later this year, 90 years after his hanging, Americans will have a fresh chance to establish whether Horn killed 14-year-old Willie Nickell, a killing that even now remains a delicate subject across the cattle farming plains of Wyoming.
Joseph Moch, a lawyer who is convinced that Horn was innocent, has persuaded a retired state supreme court judge in Cheyenne to hold a posthumous retrial after arguing that he was convicted because of a coerced confession and cooked-up evidence. 'There is no question that he did not get a fair trial,' Mr Moch said yesterday, from his office at Grand Rapids, Michigan, 'We are going to ask for a posthumous pardon.'
Horn, whose death was portrayed in the film 'Tom Horn', starring Steve McQueen, is widely regarded as the last of the great figures of the frontier era. His colourful, and violent career, took him through jobsdriving stage coaches, mining, and working as a deputy sheriff.
A brilliant tracker, he became renowned as Chief of Scouts with the US Army during their battles with the Apaches, and was an interpreter in the negotiations that led to the surrender of Chief Geronimo. He was, some claim, the only white man the Indians liked.
Towards the end of his life he was hired by the powerful cattle barons in Wyoming as a 'cattle detective' with instructions to end an epidemic of rustling. Horn used the only method he understood. He would leave a flat rock beneath his victims' heads, so that his employers would know that he was the killer. It seems he was paid by the corpse.
Willie Nickell was shot from long distance while he was riding to open a gate near his family homestead in 1901. Afterwards, while on a drinking spree in Denver, Horn was allegedly heard boasting that he was the killer. Back in Cheyenne, a US Deputy Marshall persuaded Horn to repeat the story after he had been on a 10 day drinking binge, while a stenographer hid in the next room.
The scribe scribbled down a comment that later became the equivalent of Horn's death warrant. 'It was the best shot I ever made and the dirtiest trick I ever done'. When he was hanged, his executioners had to construct a gallows in which the trap-door was triggered by a water weight because no one wanted to operate it. Some 2,500 people turned out for his funeral to pay tribute to a man whose death marked the end of an era.
But Mr Moch claims to have a stack of evidence proving that whatever else Horn may have done he wasn't guilty of child murder. He says that Horn's gun was of a different calibre from the one which killed the boy; that he was seen by a witness 25 miles from the murder site; that the jury was nobbled; that the Deputy Marshall was paid dollars 1,000 for his head, and that Horn was misquoted.
In reality, he claims, the boy was killed as a result of a feud over grazing land with the neighbouring Miller family. He promises to reveal the true murderer during the trial. But Tom Carroll, the prosecutor who will represent the state, is unimpressed. 'The state's case in 1902 was a strong one. I anticipate the same results this year.'
Mr Moch's efforts to clear his man have not been universally appreciated in Wyoming, where memories are long. 'I have already gotten hate mail from people,' he said, 'This is a touchy issue here. The whole case has been kicked around since it happened.'
But he remains adamant that a cowboy of Horn's stature could not have killed a child, and is already polishing his lines for his courtroom performance. 'Here is a man who was the only white man whom the Indians trusted and feared,' he said, 'They called him the Shadow Man and warned their children that if they were bad Tom Horn would get them. Here is a man who has been in combat situations for the greatest part of his life, who was not afraid of anyone. This is not the type of man who is going to shoot a 14- year-old kid in an ambush. He used to like to see the whites of the eyes of the people he killed. I mean, this man was the last of the legendary gunfighters. '