On 11 October 2006, while still serving in his sensitive position to the Vatican Secretariat of State, Sandri sent a letter to Father Boniface Ramsey, a New York City pastor who was a seminary professor from 1986 to 1996. Sandri mentioned "the serious matters involving some of the students of the Immaculate Conception Seminary, which in November 2000 you were good enough to bring confidentially to the attention of the then Apostolic Nuncio in the United States, the late Archbishop Gabriel Montalvo." Though Sandri never mentioned it, Ramsey's 2000 letter was about complaints of sexual abuse of seminarians on the part of Cardinal Theodore McCarrick when he was Archbishop of Newark (1986–2000). Ramsey made Sandri's letter public on 7 September 2018 to document that his letter to the Nuncio Montalvo had reached Rome and that the highest levels of the Vatican have long been aware of the charges against McCarrick. By then McCarrick had resigned from the College of Cardinals, but he still faced a Church trial. In February 2019, the same month McCarrick was laicized by the Vatican, an image Sandri's 2006 letter which illustrates Ramsey's account of his involvement in the McCarrick affair was published by the media, including in a Commonweal article which Ramsey himself wrote. The image showed McCarrick's name and Archbishop status were concealed in the letter whenever Sandri mentioned them. On 5 February 2020, journalist Thomas J. Reese cited the Sandri-Ramsey correspondence in calling for a full review of the Secretariat's files as part of the Vatican investigation into McCarrick and who in the Vatican's highest levels know what about the charges against him.