A follow-up question noted that Rossi has been accused of directing young men to Fr. Matthew Reidlinger, a priest friend of Rossi's who is alleged to have sexually harassed them in phone calls and text messages. That accusation was made in 2013.
Gregory said he was unfamiliar with the allegation.
"That's news to me. And I am not doubting it, but I have not heard about [this situation]."
"I suspect – I hope – that there is a forensic investigation. But in today's environment, even a forensic investigation that either proves or disproves, will not satisfy the people. But I would like to see that, I would like to see a forensic investigation of those allegations."
Gregory was then asked why Rossi remained in ministry at the Washington shrine; as the local archbishop, Gregory is the chairman of the board of trustees.
"It seems to me that the investigation has to come from his bishop, he's a priest of Scranton."
Acknowledging that Rossi is assigned to a Washington church, Gregory said that "the investigation has to begin with his bishop, that's just how things are done."
"Until that kind of investigation is done, a forensic one [with] outside investigators, I don't know how we can make a decision [on the suitability of Rossi to continue in ministry in Washington] until those kinds of investigations are completed."
The announcement from the Diocese of Scranton came in response to questions from CNA about whether Bambera would initiate the kind of investigation called for by Gregory.
The Archdiocese of Washington did not return CNA's calls for comment.
Attempts were also made to contact Rossi through the communications office at the Basilica of the National Shrine of the Immaculate Conception. A spokesperson for the shrine directed all inquiries to the Diocese of Scranton.
Beyond the allegations mentioned at the Aug. 13 Theology on Tap, additional accusations have also been leveled against Rossi.
In an interview in June, former papal nuncio Archbishop Carlo Maria Vigano alleged that the nunciature in Washington had received "documentation that states that Msgr. Rossi had sexually molested male students at the Catholic University of America."
Vigano also said that both the Vatican Secretary of State, Cardinal Pietro Parolin, and former Washington archbishop Cardinal Donald Wuerl were both "well aware of the situation," and that Rossi had previously been proposed for promotion to bishop and been blocked.
When he began his remarks, Gregory told the crowd of 350 young adults that he understood and shared the disaffection of local Catholics with the Church hierarchy in the wake of recent scandals which had left him "embarrassed."
"I too am let down by the leadership in the Church. I've been embarrassed. I've been embarrassed as a Catholic, as a priest, as a bishop, because of the behavior of some of my fellow clerics."
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"I know that this past year has been an extraordinarily painful year for Washington because of the revelation of behavior of two former archbishops."
"[Regarding] Theodore McCarrick, there are no words to explain the awful events that visited this local Church because of his behavior. And also Cardinal Wuerl, who while he was Bishop of Pittsburgh did many good things, but obviously there were things that he didn't do that I suspect now he is regretful of."
"I know [Wuerl's] regretful, but they too add to the sorrow that we experienced, and the embarrassment," Gregory said.
"There are no easy answers or simple solutions. All I can do as archbishop is to try to the best of my ability some sense of trust."
Earlier in the evening, Gregory introduced himself to the crowd by noting that he preferred to be up front in his dealings: "Disclosure is always better than discovery," he said.
Responding to a series of questions throughout the evening on the subject of the abuse crisis, Gregory praised the courage and witness of abuse survivors, pledging to stand with and behind them with "whatever resources we have."