The FBI has used a secret form of spyware in a series of investigations designed to nab extortionists, database-deleting hackers, child molesters, and hitmen, according to documents obtained by CNET News. One suspect used Microsoft's Hotmail to send bomb and anthrax threats to an undercover government investigator; another demanded a payment of $10,000 a month to stop cutting cables; a third was an alleged European hitman who was soliciting for business from a Hushmail.com account.