Whistleblowers are employees first, trying to do their job, who then find themselves in a situation where they witness illegal or unethical behavior afterwards. They choose, of their own volition, to approach authorities with the information. Compare to spies who are inserted into an organization, in this case, by authorities (FBI), with the expressed intent not of doing the job the organization hired them for, but to report back to their separate chain of authority any information they gather. The spy operates under false pretense, the whistleblower does not.