Daughter Accused Of Stealing At School, Advice?

Some girls in class had some jewelry a group of girls were looking at in the classroom and my daughter was accused of taking an item they claim was worth $90. She willingly showed the principal her bag that day and all the contents and did not have it. The girl (owner of jewelry) kept threatening my daughter with her lawyer parent. My daughter thinks the girl doesn't like her so is accusing her. I thought it was over but now weeks later the parent of the girl called the school police who say the parents want me to give them $90 and I refused stating that my daughter didn't have it and so the police said they are "investigating" since it is a crime. I am a single parent and this is so crazy as she already showed the school the day of she didn't have it, what do I do?