10 year old biting

[lynn1sw]

I have six children, three are from a previous relationship and grown up and live independently.  
The next three are my 10 year old step daughter, 3 year old son and 18mth old son.
My step daughter lives with her dad and i permenantly and has had no contact with her mum from the age of 3.
About 3 mths ago the baby was bitten and my step daughter told us that the 3 year old had just bit him.
This went on for 3 months, not just once or twice  a week but sometimes 6 and 7 times a day.  In fact they could not be left alone in a room for any lenght of time and the baby would be bitten.
Each time this happened the 3 year old was punished but nothing seemed to work.
I had started to wonder if there was something wrong with him because as soon as the cry would go up from the baby after being bitten, the 3 yr old would run to me crying and saying please dont get mad, im sorry im sorry.

There were also two incidents where my 2 yr old niece and my 20mth grand daughter were also bitten.  
Two make a very long story short we discovered about two weeks ago that the 3 yr old had never been biting at all and it was in fact my 10 yr old step daughter all the time.
We only found this out because she again bit my niece and my sister happened to be looking out the window and saw her doing it.
Once she was seen and questioned she admitted it had been her all along but offers no explation as to why.

We have had a few problems before the boys were born, when we had to be called to the school because she was unkind or very hurtfull to other children.

I really dont know what else to say but we are at a loss as to know what to do now so any suggestions or advice would be great.

[Mvaldivia3]

My 10 year old son keep bitting! Not just his baby bother and sister but now kids at school! What can I do to help him stop doing this?

[margypops]

Your step daughter is jealous of the attention the others get especially the 3 year old , Now she has been found out you can go about correcting it, Ask her what her feelings are about it, dont be hostile as the worst is over and hopefully with some help the biting will stop,you could get some councelling for her, explain that its is not alright for her to bite and make sure she knows it has stopped now.and you will not tolerate it. Do this in a kind and Talkative way, perhaps as this blows over,some positive attention for her she sounds as if she is sad, could her Dad do something with Just her, make her more of the Family unit, she could be feeling very left out.How is school going if its good can you build up her self esteem and Praise her aswell.