Exorcism
In Catholic practice the person performing the exorcism, known as an exorcist, is an ordained priest. The exorcist recites prayers according to the rubrics of the rite, and may make use of religious materials such as icons and sacramentals. The exorcist invokes God—specifically the Name of Jesus—as well as members of the Church Triumphant and the Archangel Michael to intervene with the exorcism. According to Catholic understanding, several weekly exorcisms over many years are sometimes required to expel a deeply entrenched demon.
Exorcism of Roland Doe
According to author Thomas B. Allen, Jesuit priest Father Walter H. Halloran was one of the last surviving eyewitnesses of the events and participated in the exorcism. Allen wrote that a diary kept by attending priest Father Raymond Bishop detailed the exorcism performed on the pseudonymously identified "Roland Doe" aka "Robbie". Speaking in 2013, Allen "emphasized that definitive proof that the boy known only as ‘Robbie’ was possessed by malevolent spirits is unattainable. Maybe he instead suffered from mental illness or sexual abuse—or fabricated the entire experience." According to Allen, Halloran also "expressed his skepticism about potential paranormal events before his death." When asked in an interview to make a statement on whether the boy had been possessed, Halloran responded saying "No, I can’t go on record. I never made an absolute statement about the things because I didn’t feel I was qualified."