The Greenbrier Ghost 

The case of the Greenbrier Ghost is a unique instance in United States judicial history where testimony from an alleged ghost was admitted into a murder trial.
In 1897, in Greenbrier County, West Virginia, a young woman named Zona Heaster Shue died suddenly. Her death was initially attributed to natural causes. However, her mother, Mary Jane Heaster, claimed that Zona's ghost appeared to her in a dream, revealing that she had actually been murdered by her husband, Erasmus Stribbling Trout Shue.
According to Mary Jane, Zona's ghost visited her for four nights, explaining that Erasmus had broken her neck in a fit of rage. Convinced by these ghostly visitations, Mary Jane persuaded the local prosecutor to exhume Zona's body.
An autopsy revealed that Zona's neck had indeed been broken, and there were signs of strangulation. This evidence led to Erasmus being charged with murder.
During the trial, the judge allowed Mary Jane to testify about her ghostly visitations, despite the defense's objections. Erasmus was ultimately convicted and sentenced to life in prison.
This case is often referred to as the only instance in US history where testimony from a ghost helped secure a murder conviction. Today, the Greenbrier Ghost is part of West Virginia folklore, and there's even a historical marker commemorating the strange event.