In 1951, he was arrested in Miami, Florida, for impersonating a priest. He was soliciting donations for a leper colony in British Guiana after he legally chartered the "Brother Mathias Foundation" (a name of his own invention- but possibly taken from the actual Brother Matthias who had befriended Babe Ruth at the orphanage that Ruth had been confined to as a child), and, unknown to the police, stole several priests' clergy shirts and a clerical collar while posing as a laundry man. He was found not guilty due to the legality of the New York state-chartered foundation, the actual existence of the Guiana leper colony, and the inability of the local clergy to expose him as an impostor. Later in his semifictional autobiography How to Talk Dirty and Influence People, he revealed that he had made approximately $8,000 in three weeks, sending $2,500 to the leper colony and keeping the rest.
By the end of 1963, he had become a target of the Manhattan district attorney, Frank Hogan, who was working closely with Francis Cardinal Spellman, the Archbishop of New York. The association of Hogan and Spellman led to the often repeated speculation that Bruce's persecution was actually fueled by his status as the original comedic Catholic Church-basher.
As a recovering Catholic myself, I have to say on that note that Lenny certainly couldn't have been that bad. In fact, I believe world-famous columnist Herb Caen said it better than anybody about Lenny's performances:
He is a rebel, but not without a cause, for there are shirts that need un-stuffing, egos that need deflating. Sometimes you feel guilty laughing at some of Lenny's mordant jabs, but that disappears a second later when your inner voice tells you with pleased surprise 'but that's true'.