12 year old Step daughter caught doing funny stuff with my almost 2 year old daughter.

I have a 12 & 8 yo stepdaughters both have the same mother. I have been married to my husband for 4 years and have a 22 month old lil girl. My 12yo has ADHD and has had numerous behavior issues of lying, stealing, sneaking around, etc. During the summer we have the girls every other week. During the school year every other weekend. My husband works full time and I work 50hrs every 2 weeks. When I am working my baby is either with my Mom or her daddy. Both step daughters are involved in the care of their sister with helping out when need be. Recently we started letting the 12 yo babysit from 30mins-2 hrs when me and my husbands hours overlap and I have a neighbor who checks in on them and is available to them. Sunday morning the girls were all in the living room together having breakfast and watching TV. My husband was still sleeping and I was getting ready for the days activities. I went to get something to drink and found my 8yo in the LR. I asked where her sisters were and she said in the bedroom. I noticed the bathroom light was on and went to turn it off. I peaked in the bedroom and seen my 12yo straddled over my baby girating(sp) herself on my baby's leg. My baby had her PJ top on and her diaper was wide open and laying under her. I stood and watched for a minute to verify what I was seeing. 12yo was "going to town" on my baby's bare leg as if she has rubbing her privates on her in a sexua| way. My baby was just laying there looking at her. When she started to whimper and fuss I said " ______ what are you doing?" She jumped off quickly and defensively as if she had been doing something wrong. I took my daughter and went outside for a minute (to smoke and take in what I just saw) I went in and talked to my husband. His response was he would talk to their mother. I made a phone call to a friend to get her advise. My husband did talk to the 12yo and she said the baby was kicking at her so she was trying to hold her down. So I called her in there and said I wasn't comfortable with what I saw and it was not acceptable. That we would talk about it more later (we were getting ready to leave and I wanted her mother to be included) I explained to her for now she was not to change the baby's diapers or be alone with her. We went on about our activities and when I dropped them off to their Mom I tried to talk privately with her. She stated my husband already called her and snottily said what's your view...because my child wouldn't do something like that. I explained that I stood at the door and watched her do it! She told me to get to my point because she was getting pissed. I told her then we don't need to have this conversation. I just thought I could come to you as a mother and try to come up with a plan to help _____, but I guess that's not gonna happen. I stood up and stated my priority is to protect my child, she stated so was hers, I said well your child needs counseling and then I left. She has full physical custody, my husband never tried for joint although he has been very involved in their lives from the beginning. He pays his support and is there for them 100%. My husband also has a very dosile(sp) personality. He doesn't like conflict and doesn't like to have to deal with stuff, especially between me and the girls mom. So I'm at a loss here on what to do. I know I can do everything in my power to protect my daughter. Safety guidelines have been put into place. But how can I make sure my 12yo gets the help that she needs???? I understand what its like to be a curious preteen , and with music videos, lyrics, and TV pushing sexua| stuff in everyone's face its almost impossible to keep them away from it, especially being in dual homes. The other factor is the ADHD and impulse control. And lastly the question of if someone has molested her to make her think that's OK to do it to her baby sister, and then what about her 8yo sister...who's to say she hasn't done it to her. Our 8yo is very quiet , shy, and a loner. There's just so many factors!!! I considered calling Cps because of their mothers uncooperativeness thinking that would be the only way I could guarantee she would get the help she needs. However with that it could make some innocent curiosity turn my 12 yo get a record and make her a sex offender. They could also make it so she couldn't be a part of her sisters life and I don't want that either. She's not a bad child, she just has some issues. I am only one person, I fear my marriage will be put on the line for this if my husband can't get on board and help me make sure his daughter gets help. I love those girls, but my main priority is to protect my baby. What do I do?!?!?! Also about a year ago there was a Cps investigation involving her mother after she whooped our 12 yo with an extension cord "to keep her from getting molested" I have spoke with my mother and a couple friends for advice...but I'm just so lost on what to do. Please offer advice or share your expierences!!! Tweet