The last thing an America bishop wanted to see was a letter from the relentless A.W. Richard Sipe, who spent more than a half-century studying the sexual secrets of Catholic clergy.

As a psychotherapist, his research files included hundreds of thousands of pages of church reports and court testimony. He estimated that he had served as an expert witness or consultant in 250 civil legal actions.

As a former Benedictine monk and priest, his private files included notes from years of work at the Seton Psychiatric Institute in Baltimore, where he counseled legions of troubled priests sent there by bishops.

"Sooner or later it will become broadly obvious that there is a systemic connection between the sexual activity by, among and between clerics in positions of authority and control, and the abuse of children," he wrote, in a 2016 letter to his local shepherd, San Diego Bishop Robert McElroy.

"When men in authority -- cardinals, bishops, rectors, abbots, confessors, professors -- are having or have had an unacknowledged secret-active-sex-life under the guise of celibacy an atmosphere of tolerance of behaviors within the system is made operative."

Sipe, 85, died on Aug. 8, even as journalists around the world produced -- often with direct links to his work -- yet another wave of news about alleged sins and crimes committed by priests and bishops. The bottom line: Sipe was a critic of the church establishment whose work was impossible for liberal or conservative Catholics to ignore.

"He was the one who -- because of his unique background -- had first-hand knowledge of the psychosexual problems in the clergy," said Leon J. Podles, a conservative Catholic scholar with years of experience as a federal investigator.