I'm a teacher here in AL, and every year we have workshops from DHR that remind us of our duty to report "suspected" child abuse. This includes our own suspicions because of a child's injuries or social issues as well as rumors. We are allowed to report to DHR or the police department, but we are required to report and we do remain anonymous (and we are immune to civil action for reporting suspected abuse if our anonymity is compromised).
I actually had a situation where I heard of a student of mine being abused in a local restaurant (at the time it was occurring). The mother chased the student into a bathroom, started beating the student in the face until she bled, then when the student fled to a bathroom stall, the mother tried to pound the stall door down. I called the police and told the principal. The next day, the mother came to the school wanting to know why "that teacher called the police to her place of employment when she was trying to discipline her child." I likely saved my job and the principal's job, because it would have come out that a student had called me to let me know what was going on and that I did not report the incident to authorities. There is more to the story regarding some disagreement over how I handled the situation, but I'm not going to put that out here on the open board. Regardless, in the end, I handled it the right way according to my values and according to the law.
From what I've read on PSU's Scout board, Pennsylvania has a similar mandatory reporting law. Paterno did not report to the authorities...period. There is some kind of nonsense about Schultz overseeing the campus police, but I can't report suspicions of child abuse to the mayor and meet my legally required duty.