Tessa Lucas is a ghost whisperer from the 19th century.  She was warned by a ghost from Weston about a strange fever before it actually came to the town.  The people thought that she was a witch and took her away from her baby, Julia E. Lucas.  She didn't know what happened to her baby and felt guilty for leaving her.  The people at the church gave the townspeople water and the tainted bread that made them lose their minds.  The tainted bread made people lose their minds and they started killing their friends & family.  The preacher rounded the people up and locked them in the St. Agnes church and set it on fire with everyone inside it.  Afterwards, they built something over the church and it is later revealed that Melinda is descended from her.