If you want the FBI to act, you need to report. They must establish violations of federal law or cross-state or financial crime. Even if it's not, report it anyways. It goes to establish the organized criminal activities and abusive nature of Scientology nationwide.
Lurkers, it's safe and confidential. You don't actually have to fill out any information about who you are or where you life if you are concerned. You can remain anonymous and still report.
Report EVERYTHING. All the abuse you've seen, every law broken, every time you were threatened or they tried to extort money from you. Every time they violated labor laws or you saw children working long, illegal hours. Every time your work or living situation wasn't safe, every time they harassed or stalked you after leaving, every single thing. It all adds up. Give as much detail as you can with any documents or photos if you have any. If not, report it anyways still. Don't be afraid.