The Conjuring: The Devil Made Me Do It

In 1981, during the exorcism of young David Glatzel, the possessing demon transfers into Arne Johnson — David's sister Debbie's boyfriend — who absorbs it willingly to save the child. Weeks later Arne stabs and kills his landlord and his legal team argues demonic possession as a defense. The Warrens investigate and find a Satanic totem buried on the Glatzel property, evidence of a curse placed by a woman named Isla, a disciple of a satanist who made a pact requiring three deaths. Ed and Lorraine trace Isla to a hidden underground chamber where she nearly drowns Lorraine. Ed, weakened by a heart attack suffered during the original exorcism, destroys the altar stone, breaking the curse and killing Isla. Arne is convicted on manslaughter charges. It remains the only known US murder case to use demonic possession as a defense.