Transcript for Exorcisms Explained: Fact and Fiction
I'm -- -- -- with an ABC -- live -- on this Halloween when we hear the word exorcism there is only one image that comes to mind. And it is considered one of the scariest movies of all time. -- -- -- -- Court the young -- in Washington DC played by Linda Blair and -- 1973 are classic. Her body suddenly possessed by the devil unleashing scenes so frightening. That when the film -- some audience members ran out of theaters crying some even vomiting. Scary stuff. And according to the man you're about to me it was not just Hollywood fiction based off a best selling book the whole story was adapted. From a -- -- real exorcism that happen in Saint Louis in 1949. Join us on this Halloween. Is Thomas Allen author of possessed the true story of an exorcism which details the reelect event that inspired the -- Thomas thanks for being with us today. We appreciate it and there. So I want -- we have so many questions to get to on this first about your book based government that -- that film and we saw the clip talk to us about that event and the boy. Specifically. Named Robbie. That was really the center of all of us. Yard it was a boy fourteen years old he lives in Maryland not far from more from Washington DC. And his family was originally from Saint Louis. In in Maryland. They consulted a Lutheran minister for the first at first because there were strange things happening in the house. Objects were flying furniture was turning over. And there were scratching on the wall things were falling. And they didn't know what it was about the minister. And couldn't help them. He saw some of the things himself and -- wrote them down. That was in January of 1949. The ministers said you better go to a priest Catholics know about this -- thing which was his way of saying. That deployment be persistent news texas'. So local priest performed an action system but as as the air criticism began he was in Georgetown University Hospital strapped to a bed. -- to loosen the -- reach under the mattress. Break off a piece of the spring and slashed the priest from shoulder to wrist took a hundred stitches to. Close the wound. That ended that -- Exorcism. The family had relatives in Saint Louis and went to Saint Louis in saint -- The a cousin was attending saint Louis university of jesuit school. She told the teacher about it and -- he and another church with both priests. Went to talk to the boy and agents -- added that the kid was probably -- -- and in need of an actress'. -- following procedures. The priest went to the archbishop there and asked for permission to perform an actress'. And that's how it got started the started of by that time it was in in march. And it lasted until April see the corrections system itself lasted about six week. So Russo Robbie this -- that of why this is 1949 has he ever been identified. -- obviously was not his real -- No no I was given a copy of the diary that was kept by their purchases during the whole. Procedure and that did have the boy's name on it I'd never use the boy's name. And I've never try never used anything that would tend to identify. Have you ever met him. No. I've heard lots of stories about him but I I know nothing to deliberately and everything I did. In the book is documented. It's there's not noses and rumors -- in his black and white 24 pages single spaced. Describing what what something like 48 witnesses -- None of them were Jesuits who come in and out of this do eventually. The -- and takes place in in a mental hospital in in them in the mental ward -- hospital in Saint Louis. And it finally ends with the boy suddenly. Saying he's school when they ask him who -- -- That he he described what he said was a kind of dream that he. And as it -- -- after by this time three and a half months of being in some sort of state. That we call possessed. And suddenly. He said he had a kind of dream. And a figure that resembles. Saint Michael the archangel with a flaming sword. -- about the demons and that boy was very. Everything I've heard since. There's one -- record saying he was merrier -- 1970. -- his first -- was named Michael. And he -- what appears to be a normal life. I've been told that he remembers nothing about what. It is obviously something that has captured a lot of attention and it's not just fans of the book -- or the movie. -- but recently there was a panel at Saint Louis University with a group of jesuit scholars terror film buffs as well. Talking about that account in 1949. Or what are the academics say about this. Well I was in that panel. It was a judge -- neither side of me. And was interesting was one judge who was talking about the spiritual basis -- the theological basis sport. And the other judge was talking about the history. And one of the things that he pointed out was that the the idea of possession the idea of exorcism. Seems to crop up and coming -- And it seems to come particularly in times of some kind of social stress. -- -- but he took it back to the sixteenth and seventeenth century. And with witch trials who -- at that time which is. Were a mystery but that it they were put under the case in the Catholic Church thinking. They were put under the concept of of being possessed. The possession and tracks back in the Bible and juices performs three purchases and in the new testament the most famous one. Is one he would tells a demon to leave for a man. And he asked the demon -- a -- Himself in the -- says we are legion. So there's more than one demon in there and Christ pulls them out and puts him in a puts them. In two or heard of -- pigs. Who then go over clip that's all in the Bible and that that biblical reference to -- system. Use news translated and Catholic theology. Into the rights of texas'. The rights of -- really consist of a series of prayers and mostly directed toward saint -- -- get out of there get out of there. Christ's command to you get -- And eventually. Those who believe the spiritual start that's what happened. So it's tough to stay with us but I want to bring in John -- archivist at Saint Louis University who helped organize this event. It John -- -- often times we will look at fiction and we look at reality and we look at the academic somewhere line in between what kind of support did you get in putting that together an event like this because. Obviously. For pop culture there is a huge amount of of attention on this but. For from an academic side. It's gotta be tough to kind of meld -- -- Well that's that's true here at the university we have pretty significant -- and us as you might imagine among our students. 1822 year old you know what our young people. All but what -- -- the panel together you know we intentionally. You know. Wanted to make it is is as professional as academic as we could. The two judgments from Tom -- One -- our vice president for the start vice president for mission and ministry. -- our coverage on -- -- a jesuit historian. Who sees you know station here in a receipt. Both of them in particular aggregate studied. The history. Of the -- Jesus but -- -- undergoes a great deal about the history of exorcism in the end mr. Allen I was -- really. Is the best you know account the most even handed policy count. Of the events of the justices -- so I think -- we tried to achieve that I think we get a reasonably good job at a -- that. All our event attracted I guess that Lisa editor -- maybe even a thousand people to this. Interestingly. A good portion of -- -- were students of student aid -- that you know partly twenty years old. All but that is. As Tom noted when he was here there were a fair number of oh middle aged and older people rational -- group had had in either. I have heard stories from their family members about you know lying or somebody who worked to -- -- -- hospital or knew someone. Was a student -- universe -- that was going on. Also as an -- combination. People in the crowd. I mean and it took about 1973 -- obviously a lot of your students were even born at a time when a film came out but and maybe I'm assuming some of them hadn't even seen the film. -- at the time so incredibly. So graphic so intense. What what I mean what was that like as far as -- panel discussion goes because -- there is a tongue in cheek element to this no pun intended. But when you but when you when you are having scholars up -- saying in fact that this actually could be based on on reality. Well I think I think you is in time we talked about this -- when he was here. This generation -- -- we have to your twilight we have you know vampires. Obviously we have the new show. -- A Sleepy Hollow there's all this. -- you know these these weird things weird creatures whatever and and I can undersea area art hope that our our our students realize that that's all that's -- story in entry -- But this you know -- was real mean this really happened. Well -- regardless of whether you believe it was disaster when he was at all those events that mr. Allen -- and -- in his book that you know based upon of the diary of one of the -- -- -- those things happen so when you're talking about you know reality. It -- you know that -- have to talk about what what what people witnessed. Thomas won every -- of this and how closely does the movie resembled the the documents that you've seen. Well on the scale -- would be down around through four OK. What are the biggest differences or that they expect as well as big differences that it was a boy not a girl. And there wasn't any had turning -- 180 degrees. But the boy was -- physical. He broke the nose of one of the Jesuits. Believe. Hit another one square in the face and caused him to police. -- had great big guys holding them down and he could we go away. -- he went into he had a normal day. Again and again the diary they talk about this boy having a normal day. He goes up to his bedroom. When he was in his aunt's house and and later in the hospital. When he goes off into sleep his sleep becomes a kind of trance. And he starts. Doing all -- -- means making obscene gestures speaking obscene words. Urinating. He never was -- a matter of vomiting but. But he he starts it always what is -- closed. He he will. -- to -- the priests and make references to their existence and in hell. All and one of the priests who was there. I interviewed several time factory in -- became good friends. He did say I don't know what to believe but I did see scratches running down one arm of the boy. It was a -- cap was striking her claws down the arm and I saw them appear. And I saw him disappear. And -- this is a guard who. Who later would would do to tourists in Vietnam. As a chaplain really in combat. And he said I saw more evil in Vietnam that I ever saw on that boy's room so was it. Evil inside the boy it was something inside it's -- talked to psychiatrists about it. Psychiatrists at that time did examine the boy. If you go to that end of the spectrum the assailant by the rational reasoning you can't find it. -- It captures the imagination and continues to fascinate Thomas Allen the book is possessed -- true story actresses and thank you so much. And of course John -- from Saint Louis University gentlemen thank you both. Very -- little. And have a very happy and safe Halloween. And conflicts of a complete report on abcnews.com. For now on Dan Butler in New York with this ABC news digital. -- --
This transcript has been automatically generated and may not be 100% accurate.