What could possibly be used as probable cause?

I was at a music festival at a private campground with private security. The security assaulted me and my friend threw us to the ground for absolutely no reason and said citizen’s arrest. Then one of them claims he heard me say that I sold 30 grams of heroin this weekend. Then they wanted to search me and I consented and had nothing to hide. They found nothing. They wanted to search my friend and he said that he’s not searching me. They beat him more and they emptied his pockets finding a small bag of meth. They then held us separately for 3 hours before calling the sheriff. After 3 hours of mental and physical abuse, they decided they wanted to search my car and I said no. I was then assaulted for my car keys and they illegally entered my car which was a mile away. They robbed me and then called the sheriff claiming I possessed mushrooms which I did not. Currently, the case is dismissed for review. I know hearsay isn't enough.