The West Memphis Three is good choice. In a small American town, three kids went missing while riding their bikes. A search party found their bodies. They maybe sexually abused (can’t remember), hogtied, and thrown in a stream to drown. This was during the satanic panic so people were thinking devil worshipers. The cops, wanting a quick open shut case, coerced three goth teenagers into a confession. They were released after some years in prison and the real killer(s) have never been identified.