Her Reasoning
Melissa was shocked that they had found her. It turned out that Kurt had converted the dumpster into a living space for her. Inside, there was cutlery, a blanket, and a lamp. Melissa had been hiding out there all along.
A fight had broken out between her and her mother, and she had run away. She had been taken care of by Kurt. However, the authorities were unaware of this.
According to them, Kurt kept her there against her will.