Marcial Maciel
How long?
Yes, Pope John Paul II did not follow up but this was because he just did not believe in the accusations. They were, to him, just too outrageous and, coming from Communist Poland, he was too aware of Communist tactics of using false charges to destroy people. He was wrong.
Even as Cardinal, Pope Benedict reopened the case against Maciel. As soon as he became Pope he removed him. Even the article states that in his last two years as Pope, Benedict defrocked 384 priests. Today the Church has very strict standards. But I guess this does not mean anything to you.