Last night I watched The Exorcism of Emily Rose (2005), a film about a girl who is possessed by demons and who dies shortly after a failed exorcism. This is advertised as being based on real events, for whatever good that does.
The film is very loosely based on the true story of Anneliese Michel (Anna Elisabeth Michel), who was born in 1952 and passed away in 1976 at the age of 23 due to malnutrition and dehydration. At the time of her death she weighed 68 pounds, had broken both knees and was suffering from pneumonia. She had been undergoing continuous exorcism ceremonies for the past year.
The entire business took place in Klingenberg am Main, Bavaria, West Germany, where I would suppose that such things as death during exorcism raise a few eyebrows. The accused, including priests and parents, were arrested, tried and found guilty of negligent manslaughter. The sentences were very light, and no one served any jail time. The interesting part here is that the sentences were a good deal heavier than the prosecutor requested, who recommended that everyone be allowed to walk away without punishment of any kind.
One argument is that the parents were protected by the German Constitution, which allows for the freedom of religion, or the free exercise of religion. In practical terms, it would seem that the judge and all the attorneys involved were either very reluctant to cross the Catholic church, or that there was more to the story than neglect, superstition and church rituals not often performed in public. I'm guessing that it was a combination of the two.
Being a religious man and having lived in haunted houses twice, I'm open to the idea of demonic possession. I do not subscribe to Catholic ritual as the only sure cure for a case of possession. Prayer will suffice.