But, considering the consequences, why not at least give the police a chance to look into it first? If the 18-year-old had committed the rape (several years prior to 2016), I'm sure they would have gotten him to slip up in the interrogation and implicate himself, or at least open the door for further investigation. And if they had come to the conclusion that he did indeed do it, but, for one reason or another, weaseled out in charging him, then it would make more sense for her to have taken the law into her own hands.
that’s why I made a point of saying “if”.