To the OP…
You can bet this behaviour from this revolting little brat is just the thin end of the iceberg, and she’s quite likely to be “known” to local authorities.
Try calling her in to local child protection services, social work dept, schools, etc: just make sure you use your most pained “more in sorrow than in anger” ToV.
Call your insurance company, and make sure they make a note of your concern: if she gets hurt on your land, and/or by your livestock, you may be liable. Instead of second-guessing yourself on who’s ultimately responsible if someone or an animal or your property gets damaged, get a hard copy from them with their answers: it’s in their best interest to hear you, and respond accordingly, and they may well take up your cudgel with the local police force.
But for all of the above, use the opportunity of your meeting with the local police to ask whether any or all of the above will work, and MAKE THEM WRITE DOWN YOUR CONCERNS.
You could also ask them to swing by your paddocks on their rounds. Tell them what each of your horses looks like; age, colour, height, etc, so if they get loose mysteriously, they’ll know what to look for.
That way, at least you’ve done due diligence.
And in the meantime, consider hiring a PI to keep an eye on your property.
Are you near a military base? Any military chums? Use that connection to your advantage - bases are full of squaddies who may lurve to keep an eye on your place for you until the little sh!t goes back to school.
If it gets worse, board your horses in the next county: I’m not kidding.
Good luck.