On 12 May 1982, he assaulted Pope John Paul II with a bayonet in Fátima, Portugal. It is unclear whether he managed to wound the Pope or not. During his trial, he said that he was opposed to the reforms of Vatican II and that he believed Pope John Paul II had been in league with the Soviet Union and even was a secret Communist agent trying to corrupt the Vatican.
He received a six-year sentence, though he served only three years, and then was expelled from Portugal, after which he moved to Belgium. By then, he had abandoned the priesthood.