The unprecedented review will examine about 5,000 cases dating from the 1950s to the present in which Scouting employees or volunteers were suspected of molesting children and were expelled from the organization, officials said.
The announcement came nine days after The Times published an investigation that found Scouting officials did not report to police hundreds of cases of alleged sexual abuse between 1970 and 1991, allowing many suspected predators to resign quietly or under false pretenses. The findings were based on a review of 1,600 files entered into evidence in a 1992 court case.
The Scouts are bracing for a wave of increased scrutiny about the past handling of abuse allegations. In coming weeks, hundreds of files from past decades will be released to the public, as a result of a petition from media organizations in an Oregon court case.
In addition to announcing its review for law enforcement, the organization this week released a summary report from a University of Virginia psychiatrist it had commissioned to analyze hundreds of files dating from the 1960s. The researcher, Dr. Janet Warren, concluded that the files, intended as a blacklist, "functioned well in helping to keep unfit leaders out of Scouting."
In an open letter released Tuesday, senior Scouting officials said the Warren study found that Scout leaders had made "a good faith effort" to keep child molesters out of the organization. The leaders also apologized for cases in which their efforts had failed.
"In certain cases, our response to these incidents and our efforts to protect youth were plainly insufficient, inappropriate and wrong," the letter said.
Warren's study initially looked at Boy Scout files on 829 men who were expelled after they allegedly abused at least 1,300 children between 1965 and 1985. She went on to review additional files.
Warren concluded that the number of men expelled from Scouting for alleged sexual abuse each year represented a tiny fraction of the more than 1 million adults who volunteered for the Scouts, and no single profile of a pedophile emerged from her analysis.
"These people look perfectly normal," she said in an interview Wednesday. "A number were married; there was a senator, a superintendent of schools, chiefs of police, firemen, laborers, school teachers."
One of Warren's central conclusions was that being involved with the Scouts "profoundly diminished" the chances that a boy would be subject to abuse.
The conclusion was based on a comparison of the number of alleged victims identified in the Boy Scout files with that in government studies of abuse reported by social service workers legally required to do so.
Some experts, attorneys and advocates for victims of sexual abuse took issue with her findings.