Ex sister in law is on heroin

Here is my soap opera. My ex husband and I separated because he was an abusive alcoholic. My brothers wife ends up leaving my brother for him and they both spiraled into a life of addiction. They treated my chasten carelessly and FINALLY I got full custody of the kids. She was just arrested last week with possession of heroin and other narcotics. Here's my question, she works at a preschool. Should I call and inform them or should I stay out of it. Also, no one in her family knows that she was arrested (she was released same day and awaiting trial). I want to tell everyone so much because she always threw karma out there but I also don't want to seem petty and bitter, even though I am at what she did to my children. Should I just stay out of it and let things fall where they may?