A friend of mine works in the social sector in Germany. She works at a school for mentally disabled children. The school is loosely related to "Waldorf"-Philosophy, which apparently makes sexuality a taboo topic. She has told me several stories of a guy who continuously makes advances on female colleagues, including her. He has a reputation to be someone to stay away from, but it's proving hard to take actions against him.
Most women don't immediately go to teachers because they regard the acts done against them as too minor to be mentioned (an inappropriate shoulder touch here, an unwanted hug there). However, my friend had an explicit experience where he wanted her to hug him, she refused and got in her car, but he pulled her out, forcefully hugged and kissed her despite her declining and struggling. Later she learnt that a lot of girls have stories to share but never dare to. So we have a ton of minor stories and one major one. There might be more that are unknown so far.
The school has no HR department to speak of. My friend went to her supervisor roughly two to three months after the incident. He told her that he would have fired the guy immediately, but he said it's statute-barred by now. There also seems to be some fear in regard to her supervisors, as the harasser's mother apparently is a highly respected doctor at the workplace. The higher-ups are generally aware of the situation but refuse to take action for "unknown reasons". She has been told if one more "concrete incident" happens, they will let him go (and he will be banned from working in the social sector). He does get called in monthly for talks about his behaviour but without effect. He also behaves suspiciously around the mentally disabled children and teenagers, but it's much too vague for allegations.
What course of action can my friend take to make sure she, her colleagues, and the children remain safe from the harasser?
UPDATE: Because we all love a happy ending - My friend spoke to her supervisors again, apparently other people had finally stepped forward after all, and this time she was taken seriously. Two weeks later the offender got fired.