My question involves criminal law for the state of: Massachusetts
My fiance and I live together. In December his daughter, who will be 16 in May, came to live with us. We've had trouble with her since she came with lies, having sex with boys, sneaking out at night and spent a week in a psychiatric hospital.
Last week the school called us in saying there was a serious problem. She has accused my 15 year old son of sexual assault. Initially at the school, I was told he was "inappropriate" with her and made her uncomfortable. They had the police there and when they came into the office I was asked to leave. (It gets worse as at the time my fiance had a couple of drinks earlier and was placed in protective custody.) My fiance kept telling them that this is wrong; he knows my son wouldn't do anything, etc. This made everyone angrier: the school, the police, Family Services. They kept saying, "Your daughter is a victim." And he kept saying, "She's not a victim. I don't know what's going on here but I don't believe this."
I spoke with my son and he said about a week earlier he asked her, "How about a kiss?" She said, "Maybe later." He put his hand on her knee and said "When?" She replied with, "Later." He left the room and thought nothing more of it.
About a week before she made the accusations, she asked her dad and I if she could go back to her old school. We told her no, that she wouldn't be changing schools until we moved. (Had plans to move out west.)
I called an attorney who told me to just wait until police wanted to question him and then to call her. The girl has been removed from our home from Family Services and is staying with my fiance's sister (at her old school.)
Both of us feel that she is troubled but that she was coerced into saying things that weren't true by a guidance counselor at school. In the meantime, Family Services has told my fiance that "just say what we tell you and you'll get your daughter back," and "You need to say you believe your daughter or you'll never get her back." The social worker also told him that my son had penetrated her on two occasions with his fingers.
I have grilled my son over this and I believe him. I can tell when he lies and by his reaction, I know he's telling the truth.
The police have not interviewed him but have interviewed three of his friends, all who have said they never saw or heard my son say anything to her.
What are the possible outcomes of this? I figure the DA can go forward or not charge him. If they do charge him, my guess is we can plea something out or go to trial. Being they are both minors, IF it went to trial and IF he was found guilty, what are the possible penalties?
It really comes down to his word against her word. He has no criminal record and both are minors, with her being slightly older. He does have some depression issues but no other mental health issues. He is also a virgin. She has had psych issues, acting out sexually, etc. Don't know if that's going to be allowed in to either a hearing or a trial.
I am worried sick over this. I used to work for the court system and know how often things get twisted.

