Just found out that neighbor girl has been spanking my boys...what do I do?

I have two boys, ages 5 and 3. There aren’t a ton of other kids in our neighborhood, but they’ve become friends with an 8-year-old girl who lives across the street. She generally seems pretty good with them, and my boys are absolutely obsessed with her. They will just play outside for hours on end.But then my 5-year-old dropped this bomb on me when getting ready for bed: “Sometimes when [the neighbor girl] gets mad at me, she’ll hit my bum and say, ‘Bad!’” He then told me that she has done it to my younger son as well.Obviously not pumped about that. I told him that it’s never okay for her to hit them or to touch their bums. I also told him to tell her she’s not allowed to do that and to come get me or my wife if it ever happens again.But I’m wondering what else I should do. Do I talk to her, or is this something I need to address with her mom (she’s a single parent)? Do I let my boys keep playing with her? It just seems so weird and uncomfortable and violating and I don’t like it.Anybody ever dealt with something similar? Any tips? via /r/Parenting https://ift.tt/2SpWW1S