One of the nation’s leading exorcists, Monsignor Stephen Rossetti, of the St. Michael Center in Washington, D.C., says that virtually all fully possessed people at one point or another experience false visions and apparitions of holy figures like Jesus and Mary.

“It’s very common,” he told Spirit Daily. “What we found is that with someone’s who’s possessed, the demons will use false visions to try to derail them or drag them into an error. So we tell them, the basic rule is, if you’re possessed, if you have some extraordinary mystical experience, regardless of what you think it is–might be Jesus or Mary or whatever, we are going to assume it’s demonic and dismiss it.”

The priest, who with a team of about half a dozen other exorcists handles the large archdiocese under the direction of Cardinal Wilton Daniel Gregory, has encountered powerful cases that go far beyond basic oppression.

“The rule of thumb is in the midst of a possession case, if you have some sort of spiritual life, the demons will try to mislead you and they will give you false visions,” he says. “We’ve seen it again and again and again. We have several big cases right now and essentially all of them have gone through that.”

This is hardly to say that Monsignor Rossetti, who once served in Air Force intelligence and has a doctorate in psychology, doesn’t believe in legitimate visions, locutions, and apparitions. Indeed, he first visited the famous apparition site of Medjugorje in the 1980s and expresses no doubts about its authenticity. The Vatican is set to issue a statement about those apparitions.

But where there is holiness, there is the devil, ready to try to muddy pristine waters.

In the wake of Medjugorje, during the late 1980s and 1990s, false and demonic visionaries flooded the Marian scene in North America, Europe, and South America.

In the case of possession, the demonic visions cause the victim to become “more possessed,” says the priest-psychologist-exorcist, whose online deliverance sessions have become hugely popular [see here].

What percent of people upon whom they perform exorcisms have such experiences?

“With fully possessed people if they try to have a spiritual life, daily prayer and that sort of thing, basically all of them, the demons will try to mislead with spiritual pride, false knowledge, false visions.”

Are demons accurate?

Sometimes they come up with what Monsignor Rossetti calls “occult knowledge.” In a major ongoing case, the demon called the priest by a nickname from his youth that no non-relative is aware of.

In fact, he said, one of the signs of a major possession is exactly such “occult knowledge.”

This had complicated discernment of alleged seers and locutionists who also sometimes exhibit such capability (which can likewise be from the good side).

“I don’t think how valid we think it is, we dismiss it,” he says of the visions. “Just trust in Jesus and pray. There are a lot of false visions today,” he added. “Maybe more so than ever. You have to be cautious. What I suggest you do is be obedient to the Church. If the Church says an apparition is good, okay. If the Church does not approve, I would shy away.”

[Resources: Monsignor Rossetti’s When the Lion Roars and Diary of An American Exorcist]

[Msgr. Rossetti’s online deliverance sessions]