Horn wandered and took jobs as a
prospector, ranch hand, and rodeo contestant, but he is most notorious for being hired by numerous cattle companies as a cowboy and hired gun to watch over their cattle and kill any suspected
rustlers. Horn developed his own means to fight thieves: "I would simply take the calf and such things as that stopped the stealing. I had more faith in getting the calf than in courts". If he thought a man was guilty of stealing cattle and had been fairly warned, Horn said that he would shoot the thief and would not feel "one shred of remorse". Horn often gave a warning first to those he suspected of rustling and was said to have been a "tremendous presence" whenever he was in the vicinity. ] In 1895, Horn reportedly killed a known cattle thief named William Lewis near
Iron Mountain, Wyoming. Horn was exonerated for that crime and for the 1895 murder of Fred Powell six weeks later. In 1896, a ranchman named Campbell, known to have a large stash of cash, was last seen with Horn. By 1900, Horn began working for the Swan Land and Cattle Company in
northwest Colorado. His first job was to investigate the Browns Park Cattle Association's leader, a cowboy named Matt Rash, who was suspected of cattle rustling. Horn went undercover as "Tom Hicks" and worked for Rash as a ranch hand while also collecting evidence that Rash was branding cattle that did not belong to him. When Horn finally pieced together enough evidence to determine that Rash was indeed a rustler, he put a threatening letter on Rash's door saying that he must leave in 60 days. Rash, however, defiantly stayed and continued working on his ranch. As Rash remained uncooperative, Horn's employers were said to have given him the "go-ahead signal" to execute Rash. On the day of the murder, an armed Horn allegedly arrived at Rash's cabin just as he finished eating and shot him at point-blank range. The dying Rash unsuccessfully tried to write the name of his killer, but no trace was left of the murder. Only the accounts and rumors from various people point to Horn as the one responsible. Rash was supposed to be married to a nearby rancher,
Ann Bassett, and the woman accused "Hicks" of being the murderer. Brown's Hole, WY.Around the same time, Horn also suspected another cowboy named
Isom Dart of rustling. Dart was one of Rash's fellow cowboys but was believed to have previously worked as a rustler named
Ned Huddleston and to have been a former member of the late "Tip Gault" gang. The gang, which had rustled cattle up in the
Saratoga, Wyoming, area, had been wiped out in a gun battle. Dart also had three indictments returned against him in
Sweetwater County. When Dart was accused of murdering Rash, he took refuge inside his friend's cabin and waited for the rumors to cool down. Horn, however, managed to track Dart to his cabin and saw him hiding together with two other armed associates. The assassin was said to have set up a sniping position overlooking the cabin from a hill, under cover of a pine tree. As Dart and his friends came out of the cabin, Horn shot him in the chest from a distance. Prior to the assassination, Horn had instructed a rancher named Robert Hudler to ready a horse miles from the murder scene for his getaway. The next day, two spent
.30-30 Winchester shell casings were found at the base of a tree where the murderer is believed to have lain in wait. "Hicks" was said to be the only one in the area to use a .30–30 rifle. The news of Rash and Dart's deaths spread throughout the territory, causing the other rustlers to scatter in fear. Horn tracked them all down and killed three other members of Rash's association. The story goes that he pinned one of the dead cowboys' ears for the homesteaders to see as a warning.
Government employment During the Wilcox train robbery investigation, Horn obtained information from Bill Speck that revealed which of the outlaws,
George Curry or
Harvey Logan, had killed Sheriff Josiah Hazen during their escape. Both were members of
Butch Cassidy's Wild Bunch, then known as the
Hole-in-the-Wall Gang, so named after their hideaway in the mountains. Horn passed this information on to Charlie Siringo, who was working the case for the Pinkertons. Horn briefly entered the
United States Army to serve during the
Spanish–American War as the chief packer of the Fifth Corps. He left
Tampa for
Cuba, where he led some of the
pack trains to the front. Horn personally witnessed the bravery of the famous
Rough Riders and
colored regiments, the Ninth and Tenth Cavalries, during their assault on
San Juan Hill, as well as the humiliating rout of American soldiers under Brigadier General
Hamilton S. Hawkins. Although the packers were noncombatants, they were still prone to attack by Cuban rebels. Horn considered himself lucky to have lost no packer during the war, although Horn recalled that he and his men were under constant fire as they delivered rations and ammunition to the soldiers. Horn continued working as a packer during the war, though he and many of his men contracted
yellow fever. At one point, he was bedridden and was deemed unfit for combat. Upon recovering, he returned to Wyoming. Shortly after his return, Horn began working in 1901 for wealthy cattle baron John C. Coble, who belonged to the Wyoming Stock Men's Association. == Murder of Willie Nickell ==