I didn’t want to weigh in while the conversation was “hot” but as someone who survived a stint in foster care, and an extremely dysfunctional childhood, I tried to both avoid catching charges and also avoid putting her back into a situation where she was suffering abuse.
She was here for about an hour before we called the police. Before we called, we checked with an attorney-friend (sorta, I told a buddy I wasn’t sure what to do and he asked his friend that practices family law). We also spoke with several of her family members. We ascertained she had run away from her mother, whom she had only lived with for a few weeks. She had been living with another family member before being kicked out. She tried to convince a friend’s family to take her in, but they refused. Privately (she used our phone, so I spoke with the other adult), they described her as someone who lies and is frequently in trouble, amongst other concerns. For a sweet seeming 13-year old, their list of concerns about her was long.

She actually ran away again the next day and returned to our place. We called immediately that time, but the police had something come up, so they took several hours. We had her watch TV while we worked.
When the police were here, my wife realized her phone was missing, and dinged it with her watch. The kid started ringing. I think everyone was surprised. She tried to run, but wound up running into a bathroom before the police took the phone from her.
We didn’t press charges about the phone. We just wanted the situation out of our life.

My understand is that she went to go live with her mother again, although her mother (with our consent via the police) actually asked us to press charges on the hope that she would be detained for a little bit and change her ways. My wife’s phone is valued above the felony larceny amount and that would follow her for the rest of her life, so we did not want to go that route.
The person being a troll was so wrong that I just couldn’t with them.