Hunkeler was an only child born into a German Lutheran Christian family and that during the 1940s they lived in the American city of [[Cottage City, Maryland|Cottage City]], [[Maryland]].<ref name="Sue Lim - Residence">{{cite book|url =https://books.google.com/books?id=_ZH_CdJpxoUC&pg=PA98&dq=Phyllis+Mannheim&lr=&cd=2#v=onepage&q=Phyllis%20Mannheim&f=false|title= Good Spirits, Bad Spirits: How to Distinguish Between Them |quote= The film ''The Exorcist'' is a the fictional rendition of a true story of possession of a thirteen year old boy named Robbie Mannheim who lived in Maryland in the 1940s.|publisher = Writers Club Press|accessdate = 2010-04-02}}</ref> Pseudonyms given to Ronald's parents in literature regarding this subject are "Mr. and Mrs. Doe" as well as "Karl and Phyllis Mannheim née Wagner."<ref name="Sue Lim - Parents">{{cite book|url =https://books.google.com/books?id=_ZH_CdJpxoUC&pg=PA98&dq=Phyllis+Mannheim&lr=&cd=2#v=onepage&q=Phyllis%20Mannheim&f=false|title= Good Spirits, Bad Spirits: How to Distinguish Between Them |quote= On Saturday, January 15, 1949, Karl and Phyllis Mannheim went out for the evening, leaving Robbie and Grandmother Wagner alone in the house.|publisher = Writers Club Press|accessdate = 2010-04-02}}</ref>
Since Hunkeler was an only child, he depended upon adults in his household for playmates, namely his Aunt Harriet (Aunt Tillie), who treated Ronald more like a special friend than a nephew.<ref name="Sue Lim - Playmates">{{cite book|url =https://books.google.com/books?id=_ZH_CdJpxoUC&pg=PA98&dq=Phyllis+Mannheim&lr=&cd=2#v=onepage&q=Phyllis%20Mannheim&f=false|title= Good Spirits, Bad Spirits: How to Distinguish Between Them |quote= As an only child, he had to depend upon the adults in the household for his playmates. One of these adults was his Aunt Harriet.|publisher = Writers Club Press|accessdate = 2010-04-02}}</ref> His Aunt Tillie, a [[Spiritualist]], who also professed [[Christianity]], saw the [[Ouija board]] as a means of contacting those who had passed on the [[Afterlife|next world]].<ref>{{cite web |title=Inspiration for the movie 'The Exorcist' has been identified as former NASA engineer |url=https://nationalpost.com/news/world/inspiration-for-the-movie-the-exorcist-has-been-identified-as-former-nasa-engineer |access-date=4 September 2023 |date=22 December 2021}}</ref><ref name="Sue Lim - Ouija board">{{cite book|url =https://books.google.com/books?id=_ZH_CdJpxoUC&pg=PA98&dq=Phyllis+Mannheim&lr=&cd=2#v=onepage&q=Phyllis%20Mannheim&f=false|title= Good Spirits, Bad Spirits: How to Distinguish Between Them|quote= Harriet responded to Robbie's interest in board games by introducing him to one - the Ouija board. Because Aunt Harriet was a Spiritualist, she saw it as a way to make contact between this world and the next. The planchette, she explained to Robbie, would sometimes move in response to answers given by the spirits of the dead. The communicated by entering the consciousness of people at the board. The spirits, Aunt Harriet said, produced impulses that traveled through the medium to the planchette, which moved obediently to spell out words or point to "Yes" or "No." Aunt Harriet seemed to have treated Robbie more like a special friend than a nephew. She had an exotic quality, especially with her talk about Spiritualism. Between visits, Robbie sometimes played at the Ouija board himself. For a Spiritualist like her, attempts to deal with the dead were neither pagan nor dangerous. Most Spiritualists considered themselves good Christians...Spiritualists, however, did not heed the biblical admonitions against consorting with spirits.|publisher = Writers Club Press|accessdate = 2010-04-02}}</ref> Like other Spiritualists, she did not heed the [[Biblical]] admonitions [[Witch|against consorting with spirits]].<ref name="Thomas B. Allen - Ouija board">{{cite book|url =https://books.google.com/books?id=_ZH_CdJpxoUC&pg=PA98&dq=Phyllis+Mannheim&lr=&cd=2#v=onepage&q=Phyllis%20Mannheim&f=false|title= Possessed: the true story of an exorcism|quote= Harriet responded to Robbie's interest in board games by introducing him to one - the Ouija board. Because Aunt Harriet was a Spiritualist, she saw it as a way to make contact between this world and the next. The planchette, she explained to Robbie, would sometimes move in response to answers given by the spirits of the dead. The communicated by entering the consciousness of people at the board. The spirits, Aunt Harriet said, produced impulses that traveled through the medium to the planchette, which moved obediently to spell out words or point to "Yes" or "No." Aunt Harriet seemed to have treated Robbie more like a special friend than a nephew. She had an exotic quality, especially with her talk about Spiritualism. Between visits, Robbie sometimes played at the Ouija board himself. For a Spiritualist like her, attempts to deal with the dead were neither pagan nor dangerous. Most Spiritualists considered themselves good Christians...Spiritualists, however, did not heed the biblical admonitions against [[Necromancy|consorting with spirits]].|publisher = [[Doubleday (publisher)|Doubleday]]|accessdate = 2010-04-02}}</ref> She therefore, introduced Robbie Ronald to the Ouija board when he expressed interest in it; between visits from his aunt, Robbie would sometimes dabble with the Ouija board on his own.<ref name="Thomas B. Allen - Ouija board"/> Nonetheless, Robbie Ronald was your average boy - he played, read [[comic book]]s, and listened to the [[radio]].<ref name="Thomas B. Allen - Adolescent">{{cite book|url =https://books.google.com/books?id=7AEvAAAAYAAJ&q=Robbie++exorcism&dq=Robbie++exorcism&lr=&cd=3|title= Possessed: the true story of an exorcism|quote= Robbie played, read comic books, listened to the radio, got under people's feet, acting like a normal thirteen-year-old boy.|publisher = [[Doubleday (publisher)|Doubleday]]|accessdate = 2010-04-02}}</ref>
On Saturday, January 15, 1949, Karl and Phyllis Mannheim went out for the evening, leaving Ronald and his Grandmother Wagner alone in the house; shortly afterwards, a dripping sound ensued and would not stop, despite the fact that every faucet was checked in the house.<ref name="Sue Lim - Dripping">{{cite book|url =https://books.google.com/books?id=_ZH_CdJpxoUC&pg=PA98&dq=Phyllis+Mannheim&lr=&cd=2#v=onepage&q=Phyllis%20Mannheim&f=false|title= Good Spirits, Bad Spirits: How to Distinguish Between Them |quote= On Saturday, January 15, 1949, Karl and Phyllis Mannheim went out for the evening, leaving Robbie and Grandmother Wagner alone in the house. Not long after...Grandmother Wagner heard a dripping sound. She and Robbie checked every faucet in the neat, well-maintained house. The could not find the source of the dripping...They finally decided that the dripping came from Grandmother Wagner's bedroom under the sloping ceiling of the second floor. The entered and while listening to the loud dripping, saw a painting of Christ begin to shake, as if some-body were bumping the wall behind the painting.|publisher = Writers Club Press|accessdate = 2010-04-02}}</ref> In an attempt to locate the origin of the sonorous dripping noise, both Mannheim and his grandmother noticed that a painting of [[Jesus Christ|Christ]] began to shake.<ref name="Sue Lim - Dripping"/><ref name="Emissary">{{cite book|url = https://books.google.com/books?id=q469xc7mbksC&pg=PA69&dq=Walter+Halloran+exorcism+ouija&lr=&cd=13#v=onepage&q=Walter%20Halloran%20exorcism%20ouija&f=false| title = A Faraway Ancient Country|quote=Once, a portrait of Christ fell off the wall.|publisher = [[Lulu (company)|Lulu]]|accessdate = 2010-03-27}}</ref>