hitting at playgroup

DD goes to a playgroup on Thurs morning for 2hours she loves it and is a maniac. Now DD hits, but its not her thats the problem as I always pull her up on it, as do other mums.

The problem is another boy at playgroup who is a couple years older then about 4-5of our kids who are the same age and play wonderfully together, and then there are a couple of even younger ones. He is quite agressive/violent. I was told one day he threw a truck at an 11mth old. He went up to one of the little girls today and just whacked her repeatedly on her head. She was at her mums side but her mum didn't see it so I removed her from the situation to play with my DD. All his mum did was say no. Normally all she does is say use your words and things like that, or says he's having a bad day or even better blames it on the father (single mother). The mum is a good friend of one of the woman from playgroup but she doesn't feel she can say anything and is going to the extent of ignoring her and not inviting her to do things.

Our poor children are being bullied by this boy. DD will stand up for herself and is likely to wallop him back, although not ideal and I don't condone her hitting. I tend to try and keep her away as she's a feisty little thing with an attitude to match. If it were one of the other mums I would say something but I don't know her well enough and she doesn't really click with us. He's also not one of the children I feel I can tell off (quite a few of us are happy to tell each others kids off, if its hitting or putting people in danger).

That doesn't really make sense.

But suggestions please, what can I say or do to help this woman see that her son is a little out of control. I've suggested to my friend that she uses I statements, such as I get upset when I see X strike out at Y when she is happy playing. As I said she doesn't feel comfortable with it. I have wondered if we mention it to the playgroup coordinator but she is just a mum herself and she already does so much

Bizzys is a good suggestion I am just abit more woosie and would say very loud. Oh no we don't hit here that isn't very nice is it so that the mum hears. I would say it in a nice voice and not a growly voice but firm still. Even if mum doesn't hear it it brings it to the attention of the other mums and maybe one of them is more confident and says something. Probably not the right way to do it but I have done it this way before and it was sorted.

I agree with what Bizzy said.  Just be upfront and take the child immediately to his mother the next time he hits and tell her its not acceptable.  I would imagine it would be hard to be the mother of a hitting child, but this mum doesn't seem too bothered!  Just tell her straight up if you can. 

Goodluck.