The 19th century was an interesting time in human history. We were on the cusp of technological superiority, leaving behind many preconceived notions, yet we were still in the dark ages when it came to some subjects, like ghosts and the supernatural.
For instance, take the case of the Hammersmith Ghost. Hammersmith was a village that is now part of London proper. For nearly two months, the village of Hammersmith had been plagued by a "ghost". The "ghost" was violent, assaulting men and women, both physically, and through intimidation. For weeks it managed to evade detection.
Francis Smith, an excise tax collector, went on a hunt for the ghost with the help of the village night-watchman William Girdler. Unfortunately for Smith, when he managed to catch up to the ghost, he shot and killed it. Though as you likely guessed, it was not a real ghost, but a man dressed up as one. The ghost that Smith had mistakenly murdered turned out to be Thomas Millwood, a local resident.
This case was going to confuse British courts for months to come.