By Pat McGonigle
St. Louis (KSDK) -- It's one of the biggest questions about the most well documented cases of an exorcism in U.S. history.
What ever happened to the 13-year-old boy at the center of the exorcism performed by Jesuits at Saint Louis University?
The story was the basis for the best-selling book and blockbuster horror movie, "The Exorcist."
With a few rare exceptions, the boy's identity has remained a closely guarded secret for decades.
"He's still alive," said David Waide, SLU archivist.
In almost all of the accounts of the famous case, the boy is referred to as "Robbie."
Robbie's ordeal began at his home in Maryland in 1949. Bizarre, unexplained things started happening in Robbie's home, up to and including marks and welts on his body.
Robbie's parents came to St. Louis to stay with relatives, partially in hopes that a change of scenery would stop the unexplained activities.
It didn't help.
One of Robbie's cousins was a student at St. Louis University at the time. She relayed accounts of Robbie's ordeal to Jesuits at SLU.
Eventually, Fr. William Bowdern, S.J. led the exorcism with the help of Fr. Raymond Bishop and Fr. Walter Halloran, among others.
The ordeal ended at a now-demolished wing of the Alexian Brothers Hospital in south St. Louis.
It's believed Robbie would be 77 today.
"He's had several children," Waide said. "He's moved back to the Washington D.C. area. He was non-Catholic, Lutheran nominally, but he became a Catholic. He was baptized during this whole episode."
It's been reported that Robbie named a son Michael. In the exorcism records, Robby tells the priests he was saved by St. Michael the Archangel.
Robbie returned to St. Louis two years after his ordeal ended in 1949.
In a priest's diary about the exorcism, this is the final footnote entry on page 29:
"Follow up: August 19, 1951. R and his father and mother visited the Brothers. R, now 16 is a fine young man. His father and mother also became Catholic, having received their first Holy Communion on Christmas Day, 1950."
You can read the entire diary on KSDK.COM.
Story: SLU expert talks about exorcism on campus