ULPT Request: Random person spilled a bucket of dirty water on me. What do I do?

I was crossing the street with my kid to help an older guy with a walker who was a bit stuck and couldn't get off the street. When we were standing on the sidewalk next to each other, - suddenly SPLASH - and we were both soaking wet (my kid wasn't hit).

Apparently some mid-aged lady purposefully threw a bucket of dirty soap water on us from her flats balcony on the second floor. My kid and others had seen her doing it. She was then hiding inside and didn't come out when we were calling for her. I was waiting for her on the other side of the street for a few minutes and saw her when she was taking a look whether we were still there. She immediately went inside again when she saw me.

I know where she lives, especially which balcony is hers.

Dear Reddit, what is my next move?