While it is impossible to deduce exactly what actually happened, several sources point towards the fact that the real Annabelle was a gift given to a student-nurse named Donna on her birthday in 1971. The doll was a hand-me-down from a hobby store, and Donna was initially thrilled to have gotten Annabelle. Soon, Donna and her roommate Angie began to notice strange behavior exhibited by the doll, where micro-movements gradually escalated to more aggressive ones, such as when the doll moved from one room to the next. While this could have been a simple case of shared paranoia, the girls’ mutual friend, Lou, believed that the doll was possessed, and soon after, sinister notes were found strewn all across the apartment, including ones that said “Help Lou” or “Help us.”
Even after these strange things occurred, Donna and Angie tried to rationalize them to the best of their abilities. However, one day, Donna returned home to find the doll with blood on its hands, which prompted the arrival of a medium. The medium told the girls about the death of a child named Annabelle, whose spirit was allegedly attached to the doll, which led Donna and Angie to try their best to accommodate the seemingly possessed doll. After Lou suffered scratch marks when no one was home, the Warrens came in soon after and deduced that Annabelle’s goal was to take possession of Donna’s soul.
While there is no way to actually support or debunk these events, it is clear that the involvement of the Warrens led to the doll being kept in the duo’s now-closed occult museum, where it still resides. The Warrens took Annabelle with them after declaring that the doll was possessed and allegedly encountered strange phenomena on their way back, including object levitation and vehicular mishap.