A warning about amateur sleuths in my town digging into cold cases

I live in a small town where a group of true crime fans started looking into a decades-old disappearance. They've been posting theories online and even visiting the family of the missing person. Last week, they shared a photo of a potential suspect's house, which isn't right. This kind of thing can scare people and hurt the real investigation. We should be careful not to overstep when we try to help. Has anyone else dealt with sleuths going too far in their community?