Francis decided that information from a preliminary probe should be combined with a "further thorough study" of McCarrick's archives, a Vatican statement said Saturday.
McCarrick, a former archbishop of Newark, N.J., and Washington, D.C., already resigned from the College of Cardinals in July amid fallout from Archdiocese Review Board investigation into allegations he abused a teenage altar boy decades ago, while he was a priest of the Archdiocese of New York. A man accused him in September 2017 of sexually abusing him in the 1970s.
The Archdiocese Review Board, made up of jurists, law enforcement experts, parents, psychologists, a priest and a religious sister, according to an Archdiocese of New York statement, found that the allegations were "credible and substantiated," according to an Archdiocese of New York statement.
The goal of the further study is "to ascertain all the relevant facts, to place them in their historical context and to evaluate them objectively," a Vatican statement said.
U.S. bishops had requested the investigation into McCarrick's history of sexual abuse in August and criticized Francis for not approving the request sooner.
"It was an expression of what the bishops in this country felt was the right thing to do," Bishop Robert Barron, who is part of the administrative committee of the United States Conference of Catholics Bishops, said Thursday. "We asked the pope specifically to launch an investigative process."
USCCB President Cardinal Daniel requested the probe on Aug. 16 to look into how McCarrick rose through the ranks of church leadership after the Archdiocese Review Board's findings surfaced.