[Editor’s note: Crux is publishing an occasional series of brief profiles in the ongoing drama surrounding clerical sexual abuse, ex-Cardinal Theodore McCarrick, and accusations of cover-up against various Church officials including Pope Francis.]

ROME – If there’s anyone who arguably holds the key to unlocking everything the Vatican knew about the scandals surrounding ex-Cardinal Theodore McCarrick, that person is Canadian Cardinal Marc Ouellet.

Currently Prefect of the Vatican’s Congregation for Bishops, Ouellet sits atop a department which, according to former Vatican ambassador to the United States Archbishop Carlo Maria Viganò, contains a “thick” dossier on McCarrick, who lost his red hat in July after accusations went public that he had abused minors nearly 40 years ago.

Viganò published a letter Aug. 25 making a series of accusations against both current and former Vatican officials, including Pope Francis, arguing that he told the pope about McCarrick’s alleged misconduct with seminarians in 2013, and Francis ignored restrictions put into place by Benedict XVI and instead turned to McCarrick as a key advisor.

Since Viganò published his letter, there has been no word from the Vatican either confirming the existence of the dossier or denying it. With the U.S. bishops set to launch investigations into four dioceses at the heart of the McCarrick saga, all eyes are increasingly turned to Rome and whatever secrets it may possess.

A thick dossier

Born in La Motte, Quebec in Canada in 1944, Ouellet was ordained a priest with the Society of Priests of Saint Sulpice in 1968, and just two years later moved to Colombia to teach philosophy at the Major Seminary of Bogotá.

In 2001 he was named secretary of the Vatican’s Council for Promoting Christian Unity. Prior to that, much of his career had been spent either as a professor or rector of seminaries.

Ouellet held the position in the Vatican’s office for Christian unity for just one year before being named Archbishop of Quebec in 2002, a post he had for seven years before his 2010 appointment by Benedict XVI as Prefect of the Vatican’s Congregation for Bishops and President of the Pontifical Commission for Latin America in 2010.

Having held those positions for only three years when Benedict resigned in 2013, Ouellet was confirmed by Francis, meaning he’s stayed in his roles for some eight years now. He originally stepped on board in Rome four years after McCarrick’s retirement from Washington, D.C.

In his letter, Viganò wrote that before heading to Washington as the Vatican’s ambassador in 2011, Ouellet informed him that Benedict XVI had placed private restrictions on McCarrick, among other things forbidding him from celebrating Mass in public, traveling, giving lectures and living in the seminary where he moved after retirement.

Ouellet, Viganò said, had been informed by his predecessor in the bishops’ office, Cardinal Giovanni Battista Re, about the sanctions, and had communicated them to him in November 2011, before he left for his post.

The sanctions, he said, “were included among the instructions of the same congregation to the new nuncio,” using the Vatican word for an envoy.

In turn, Viganò said that after arriving in Washington he spoke to McCarrick about the sanctions. During the conversation, he said, McCarrick admitted “that he had perhaps made the mistake of sleeping in the same bed with some seminarians at his beach house,” but had used a tone “as if it had no importance.”

In his latest statement, published Sept. 29, Viganò issued an appeal to Ouellet to publish the dossier on McCarrick, saying he had always worked in “harmony” with the cardinal and that he has always “had great esteem and affection towards him.”

However, Viganò said that while at the beginning of Francis’s pontificate Ouellet “maintained his dignity,” in the five years since he’s been “undermined” by two homosexual allies of the pope, who were a part of Ouellet’s department but who went over his head to suggest bishop candidates to Francis directly, leading the cardinal eventually to “give up.”

For Viganò, this surrender culminated in a lengthy article by Ouellet for the Vatican’s newspaper, L’Osservatore Romano, titled “Accompanying, Discerning and Integrating Weakness,” and which praised the Jesuit approach to “pastoral discernment,” particularly in reference to complicated and irregular family and marital dynamics.

According to Viganò, the article represented Ouellet’s “surrender” to Francis.

Viganò addressed Ouellet directly in his letter, saying, “Before I left for Washington, you were the one who told me of Pope Benedict’s sanctions on McCarrick. You have at your complete disposal key documents incriminating McCarrick and many in the curia for their cover-ups. Your Eminence, I urge you to bear witness to the truth.”

In the meantime, Ouellet reportedly has turned over his department’s archives to the Vatican’s Secretary of State, Italian Cardinal Pietro Parolin, who, sources tell Crux, is collecting documentation on McCarrick.

To date, Ouellet has only responded publicly to Viganò’s charges once, during a meeting of European bishops in Poland.

On that occasion, Ouellet called the charges against the pope “a very bad example” and “a very serious offense,” not to mention a “not positive” answer to the abuse crisis and “an unfair attack.”

“To express solidarity with the Holy Father… is a conditio sine qua non of solidarity between ourselves as bishops to bring forward the mission of the Church,” Ouellet said, using a Latin phrase that means roughly “a condition without which not.”