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, said Grein’s attorney, Patrick Noaker.

The development is significant, given that the Vatican investigation against McCarrick has already created a credibility crisis for the Catholic hierarchy including Pope Francis.

It was apparently an open secret that McCarrick had slept with adult seminarians.

Grein’s testimony, however, includes allegations that McCarrick, a former family friend, also groomed and abused him starting when he was 11.

The Manhattan District Attorney’s office launched a hotline last year and invited victims to report even decades-old sex abuse, saying it would pursue “any and all investigative leads” to ensure justice.

Grein met with Sullivan before Christmas after filing a compensation claim with the New York City archdiocese.