VATICAN CITY — The key accuser in the sex abuse case against ex-Cardinal Theodore McCarrick has met with New York City prosecutors, evidence that the scandal that has convulsed the papacy is now part of the broader U.S. law enforcement investigation into sex abuse and cover-up in the Catholic Church. James Grein gave testimony last month to Manhattan Assistant District Attorney Sara Sullivan, who is investigating a broad range of issues related to clergy abuse and the systematic cover-up by church superiors, Grein’s attorney, Patrick Noaker, told The Associated Press. The development is significant, given that the Vatican investigation against McCarrick has already created a credibility crisis for the Catholic hierarchy including Pope Francis, since it was apparently an open secret that McCarrick slept with adult seminarians.