Tthe courts have proven that there is no expectation of privacy in AA unfortunately. You can be compelled to testify in a court of law and you could be charged with harboring information on a criminal act if you fail to report information to the proper authorities. Sharing in a ‘general way’ is advised on all levels IMO as a sponsor and as to what a sponsee shares. Lawyers and clergy are the only protected class when it comes to safeguarding secrets. The sponsor in this case could have advised that the person turn themselves in, after all how could they complete the 12 steps w/o properly cleaning house? Barring that she (I assume it was a woman sponsor) had every right to feel compelled to turn that person in by the nature of the crime - all my opinion of course.
I know about the legal side of it all, and am not surprised. The problem is the sponsor did not have to come forward of their own volition like they did.