Fr. Boniface Ramsey, the whistleblower whose quiet campaign to warn Church officials about Archbishop Theodore McCarrick’s alleged misconduct with seminarians recently came to light, just fired another shot across the bow of the Vatican.

On Sept. 7, Fr. Ramsey provided a letter confirming that top officials in Rome were aware of McCarrick’s behavior in 2000, the same year that he was appointed archbishop of Washington, D.C.

The letter in question was written by then-Archbishop Sandri, the third-ranking official for the Vatican’s Secretary of State who is now the Cardinal Prefect for the Congregation for Eastern Churches. It is dated Oct. 11, 2006, months after Benedict accepted McCarrick’s resignation, following his 75th birthday, and references Fr. Ramsey’s previous 2000 letter, which warned the Vatican about McCarrick’s behavior,

Archbishop Sandri never mentions the U.S. Church leader by name — the purpose of the letter was to ask Fr. Ramsey’s opinion of a former New Jersey seminarian who was being considered for a Vatican post.

And yet, though McCarrick was not the focus of the letter, the archbishop’s oblique reference to Fr. Ramsey’s disturbing report signals that the Vatican official had reviewed the priest’s claims.

Catholic News Service, the U.S. bishops’ news organization, underscored the significance of the letter, particularly in the wake of Archbishop Carlo Maria Viganò’s bombshell “testimony” that accused Vatican officials of shielding the now-disgraced Church leader for almost two decades.

“Archbishop Sandri's letter is significant because it corroborates Ramsey’s story as well as Viganò's claims,” reported CNS.

On Aug. 28, when I spoke with Fr. Ramsey about his 2000 letter to the Holy See, he never mentioned that he possessed such a letter. At the time, he said the Vatican had never formally responded to his charges, though he also said he was sure the letter had been read.

On Sept. 10, Fr. Ramsey told me that he began looking for Archbishop Sandri’s letter after reporters had pressed him to explain how he knew the Holy See had reviewed the allegations contained in his 2000 letter.

“I didn’t think I had the letter, but found it in a folder,” he said.

But while CNS’s report suggested that the letter implicated the previous pontificates of Pope St. John Paul II and Pope Emeritus Benedict XVI in a decades-long cover-up of McCarrick’s misdeeds, Fr. Ramsey emphasized that the 2006 letter came from an official who was the third in command at the Vatican’s Secretary of State.

“This letter doesn’t implicate any pope,” he argued.

Still, he called it an important “missing link.”

“It helps to prove the letter was received.”

Eighteen years after he wrote his letter outlining complaints about McCarrick, the Vatican’s belated reply has surfaced at a critical juncture.

Cardinal Daniel DiNardo of Galveston-Houston, the president of the U.S. Conference of Catholic Bishops, has proposed an Apostolic Investigation that would identify the U.S. Church leaders and Vatican officials who shielded McCarrick’s alleged misconduct.

Cardinal DiNardo will meet with Pope Francis Sept. 13 to discuss the sex scandals in the United States. The 2006 letter gives Cardinal DiNardo additional leverage for his proposal, and could make all the difference.

The priest is a pastor of St. Joseph Church in the Yorkville neighborhood of New York City. But from 1986-1996, he was a Dominican academic who served as a professor at Immaculate Conception Seminary (based at Seton Hall University), and in that capacity he received reports about McCarrick’s misconduct.

I asked Fr. Ramsey to explain why he was one of just a small group of people who raised the alarm about McCarrick, at least based on public reports. After all, he served at the seminary for 10 years, and the reports about McCarrick’s alleged misconduct were no secret.

The priest said he didn’t know why others from the seminary faculty did not come forward but might have had something to do with the fact that he was a Dominican, not an archdiocesan priest.

“I was something of an outsider.”

He also suggested that McCarrick’s behavior was viewed by many as “odd” or even “crazy,” but not necessarily immoral.

“The term, ‘sexual harassment,’” had not gained currency, and the seminary administrators didn’t know how to react, he ventured.

“I am trying to understand it from the perspective of people at that time.”

In the wake of the #MeToo movement, Fr. Ramsey has gained the public’s respect as a whistleblower who tried to stop a powerful Church leader who abused his authority.

But when asked to share the reactions of his fellow priests he had little to report.

“I haven’t heard from any priest in my deanery,” he admitted, and didn’t try to explain why that might be.

Nevertheless, he has decided to push ahead and speak about the issues that have drawn him into the public eye during his next Sunday homily.

“There is a Latin phrase,” he said, that describes his own state of mind: “’Fiat justitia ruat cælum’ — ‘Let justice be done though the heavens fall.’”