A newly revealed 1997 letter from the Vatican warned Ireland's Catholic bishops not to report all suspected child-abuse cases to police - a disclosure that victims groups described as the smoking gun" needed to show that the Vatican enforced a worldwide culture of cover-up. The letter, obtained by Irish broadcasters RTE and provided to The Associated Press, documents the Vatican's rejection of a 1996 Irish church initiative to begin helping police identify pedophile priests following Ireland's first wave of publicly disclosed lawsuits.Child-abuse activists in Ireland said the 1997 letter should demonstrate, once and for all, that the protection of pedophile priests from criminal investigation was not only sanctioned by Vatican leaders but ordered by them. "The letter is of huge international significance, because it shows that the Vatican's intention is to prevent reporting of abuse to criminal authorities. And if that instruction applied here, it applied everywhere," said Colm O'Gorman, director of the Irish chapter of human rights watchdog Amnesty International. The Vatican does advise bishops worldwide to report crimes to police - in a legally nonbinding lay guide on its Web site. This recourse is omitted from the official legal advice provided by the Congregation for the Doctrine of the Faith and updated last summer. That powerful policymaking body continues to stress the secrecy of canon law.