Over two decades, the Boy Scouts of America failed to report hundreds of alleged child molesters to police and often hid the allegations from parents and the public. A Los Angeles Times review of 1,600 confidential files dating from 1970 to 1991 has found that Scouting officials frequently urged admitted offenders to quietly resign - and helped many cover their tracks. Volunteers and employees suspected of abuse were allowed to leave citing bogus reasons such as business demands, chronic brain dysfunction" and duties at a Shakespeare festival. The details are contained in the organization's confidential "perversion files," a blacklist of alleged molesters, that the Scouts have used internally since 1919. Scouts' lawyers around the country have been fighting in court to keep the files from public view. As The Times reported in August, the blacklist often didn't work: Men expelled for alleged abuses slipped back into the program, only to be accused of molesting again. Now, a more extensive review has shown that Scouts sometimes abetted molesters by keeping allegations under wraps. In the majority of cases, the Scouts learned of alleged abuse after it had been reported to authorities. But in more than 500 instances, the Scouts learned about it from boys, parents, staff members or anonymous tips. In about 400 of those cases - 80% - there is no record of Scouting officials reporting the allegations to police. In more than 100 of the cases, officials actively sought to conceal the alleged abuse or allowed the suspects to hide it.