In January 1949, a 13-year-old boy in Washington, D.C., began exhibiting disturbing behavior that left his parents baffled and terrified

He was calm and normal during the day, but at night, he would suddenly erupt into screaming fits and other wild outbursts. Meanwhile, he would enter a trance-like state, make sounds in a guttural voice, and break out in scratches and red lines all over his body.

After getting nowhere with doctors, his horrified parents called in Jesuit priests to carry out a harrowing series of exorcisms. As they desperately tried to wrest the demons from his body, they claimed that the boy's bed moved on its own, slid violently across the room, and knocked them over. They also said that he would shout obscenities in Latin, a language he had never learned. And when they discovered that the boy's chest was marked with the letter X in red welts, the priests took it as a sign that he was possessed by 10 demons.