Trivia: The "Annabelle" doll seen in the opening sequence of the film was actually a regular "Raggedy Ann" doll in the real-life story that inspired the scene. The doll was redesigned to its current, much more grotesque form for several reasons: First, to make it more cinematic. And second, to avoid legal troubles with the copyright holders on Raggedy Ann. The filmmakers and Lorraine Warren also stated that they were interested in re-designing the Annabelle doll because they were afraid if they used a real Raggedy Ann doll, it would frighten children who might own them.
Trivia: The film is loosely inspired by a real-life paranormal investigation by investigators Edd and Lorraine Warren, though new elements were added to the story in order to make it more cinematic.
Trivia: In the film, they find their dog dead next to the house. However, in the real story this is based on, the dog actually died at their previous home. It was a bad neighbour boy who broke into their previous house and wound up killing their dog. Andrea jumped on the boy and was screaming she was going to kill him until the family pulled her off. This is supposedly the reason the family moved in the first place to the house this film is set at.
Trivia: At the Warren's presentation, there is a cameo of the real Lorraine Warren in the audience.
Answer: She was a witch that committed suicide. Before, she cursed everyone who set foot on her property.