Des, what I found out in my own therapy as a molested child is that
a three year old doesn't have a clue what sex and/or the genitals are about. Someone had to teach me, as well as those little kids, what sex is about! It is NOT normal behavior for a three year old!
I hope CPS has more on the ball where you live than where I live. They cause more problems here than they are worth!
Did you say your friend was sexually abused as a child? Could it have been her brothers?? At any rate, if CPS is worth their salt, it should be THEY that investigate who is doing this.
It sure is a tough one to call. Tread carefully as you go!
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Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.