inheritances, large payments for being scammed

Seven or more years ago I was scammed of money through fake money orders, followed by payments sent to Nigeria; Lagos, Benin supposedly to recoup money lost to scammers. I have been compiling a folder with sender's names etc.
I'd like to expose these people to authorities, but don't know where to begin. Can anyone direct me? I receive 2-3 emails per day offering me huge sums, for various fee amounts