It is easy to explain why the people of Exeter believed Mercy to be a vampire. When compared to the bodies of her mother and sister, hers looked pristine. We know now that this was because Mary and Mary Olive died several years earlier, and had been buried underground for some time. Mercy’s body, on the other hand, had effectively been placed in a freezer due to the frozen ground. This greatly slowed down her body’s decomposition, causing the townspeople to believe she was undead. We also know that the hair and nails appear to grow on a corpse because the skin starts to shrink away as it dries after death. This is what had happened to poor Mercy.