It is possible that Jessica's mother had to call the cops one day because Jessica's behaviour was strange and/or threatening.
I have a life experience to share with you. About three years ago, my father lived with one of my brothers (who was 25 at the time). My brother started drinking socially, and then alone at home. One night, my father had to call my sister because my brother was chasing him through the house, making threats to kill him. My father got out of the house, wearing only pajama bottoms, with no car keys, afraid that my brother would come and get him outside. My sister arrived just in time. He jumped into her car and she managed to drive out of the driveway before my brother could get to the car.
This was the first time that was my brother was acting like that so my father didn't press charges but urged him to stop drinking. Then, about one month later, while my father was away at friends', my brother nearly destroyed the house. He broke everything in sight (even the basement staircase, toilet seats, TVs, etc) and emptied a fire extinguisher in the bedrooms. When he came home, my father called the police. Yes, he loved my brother but he was now afraid of him, and also the insurance company told him that he had to press charges otherwise he wouldn't be covered.
It turned out that my brother has a mental disorder called borderline personality that gets aggravated by alcohol abuse. He had to go to therapy and even to mental institutes. Twice.
Why am I sharing this? Because, as you said, it usually does take a lot for a parent to call the police on their children. But it does happen. And mental illnesses are often not diagnosed until something big happens. Moreover, most parents won't dare to speak about it to others in fear of judgement.
In Jessica's case, perhaps she had a mental illness. Perhaps she was using drugs that caused her to get paranoid and then act violently or in a very weird way. Drugs make people do strange things sometimes. Or perhaps she was just a typical 19 year old teenager girl having trouble to get along with her parents.