William Hare was believed to have been born in Ireland, although his exact birthplace and year are unclear. Estimates place his birth somewhere between 1792 and 1804. Like many Irish laborers of the time, he moved to Scotland for work, eventually settling in Edinburgh. There, he found employment helping build the Union Canal.

In the early 1820s, Hare became involved with a woman named Margaret Laird, the widow who ran a cheap lodging house in the West Port area of Edinburgh. After marrying her, Hare took over the day-to-day management of the property. It was in this crowded, working-class part of town that he met William Burke.

Hare was described as being less charismatic and more secretive than Burke. While Burke did most of the talking and was considered more personable, Hare was cunning and manipulative behind the scenes. Together, they became a deadly team.

The series of murders started in late 1827 when an elderly lodger at Hare's boarding house died owing money. Instead of reporting the death, Hare and Burke sold the corpse to Dr. Robert Knox, an anatomist at a private medical school. Knox paid them handsomely, and they quickly realized there was big money in supplying fresh bodies.

Rather than wait for more natural deaths, the pair began actively hunting victims. Over the next ten months, they lured 16 people—many of whom were vulnerable or unnoticed by society—into their boarding house. After intoxicating them with alcohol, Burke and Hare suffocated their victims by pressing down on their chest and covering their mouth and nose. This left no physical marks, which was important for selling the bodies.

Hare helped dispose of bodies and collect payment, often taking an active role in the killings. But when they were finally caught after the murder of Marjory Docherty on October 31, 1828, Hare quickly struck a deal with prosecutors. He agreed to testify against Burke in exchange for complete immunity from prosecution.

This deal sparked massive public outrage, but the authorities believed it was the only way to secure a conviction. Hare's testimony was crucial in sending Burke to the gallows. After Burke’s execution, Hare was quietly released in early 1829.

What happened to William Hare after that is still a mystery. Some say he changed his name and moved away, others claim he was blinded by an angry mob. But officially, he vanished from public record.