Gilles Garnier was a reclusive figure living during the 16th century in the rural wilderness of eastern France. He made his home in the area of Saint Bonnot, near the villages of Amanges and Dole, located in the historical County of Burgundy (now part of the Franche-Comté region). Locals referred to him as "The Hermit of St. Bonnot" due to his isolated and withdrawn lifestyle. Garnier was reportedly a former resident of Lyon or its surroundings before settling in this rural area.

Garnier's reclusion became more complicated after he married a woman named Appoline. Having lived alone for so long, he struggled to provide food and basic needs for his new family. Their union quickly fell into discontent, largely due to their impoverished condition and his inability to support more than himself. These personal struggles unfolded against the backdrop of a superstitious and fearful society, where folklore about witches and werewolves remained deeply rooted.

In his early years, Garnier had already developed a reputation for being suspicious among the villagers. He was involved in trespassing disputes with locals and was often seen roaming the woods.

Between 1572 and 1573, the quiet rural region near Dole was shaken by a series of brutal and horrifying child murders. Several children vanished or were discovered dead, mutilated in grotesque fashion. As panic spread, the authorities of Franche-Comté issued an official edict permitting locals to hunt down and kill whoever was responsible for these atrocities. At the time, unsolved violent crimes were often blamed on werewolves, a belief still widely held.

Gilles Garnier’s downfall began when a group of workers spotted what they believed to be a large wolf with a child’s body in its grasp. As they got closer, some recognized the figure as the local hermit, Gilles Garnier. Suspicion quickly turned into accusation. Garnier was arrested shortly after and brought in for questioning, where his confession was extracted under torture.

At trial, Garnier admitted to murdering at least four children, all aged between 9 and 12. According to his testimony, while foraging in the woods for food, he encountered a spectre that offered him a magical ointment. The ointment, said to transform him into a wolf, would supposedly make it easier to hunt animals for sustenance. Garnier claimed to have used this ability to hunt, and eventually kill, children, consuming their flesh in a desperate attempt to feed himself and his wife.

The first documented murder occurred in late August 1572, just before the end of the Feast of Saint Bartholomew. Garnier attacked a 12- or 13-year-old boy near the towns of Perrouse and Cromary, ripping the boy’s body apart and opening his belly with savage bites.

The next killing took place in late September or early October 1572, around the Feast of Saint Michael. Garnier abducted a 10–12-year-old girl from a vineyard near Châtenois. He strangled her, disrobed the body, and consumed the flesh from her thighs and arms, later taking some meat home to share with his wife.

In mid-October 1572, Garnier killed a 10-year-old boy near Gredisans and Menote. Again, he cannibalized the boy’s body like eating flesh from the thighs and stomach and tearing off a leg to consume later. In that same attack, he also attempted to strangle another boy but was interrupted by nearby villagers.

His final recorded attack happened between November 1-8, 1572, in a meadow near Le Pouppe, between Authume and Châtenois. Garnier assaulted another girl, biting and scratching her before strangling her. He was again interrupted, and the girl died from her injuries a few days later.

Over 50 witnesses testified against Garnier during his trial. Some claimed they saw him as a man, others swore they saw him as a wolf. He was convicted not only of murder and cannibalism but also of lycanthropy and witchcraft, both considered capital crimes at the time.

Gilles Garnier was burned at the stake on January 18, 1574, a common method of execution for crimes tied to sorcery and heresy. Despite the religious nature of the charges, his trial was handled by secular authorities rather than the Inquisition.