Matt Edman is a former Tor developer that helped the FBI to hack and de-anonymize Tor users in several court cases, including the clamorous Operation Torpedo and Silk Road.
He helped the Feds in developing a custom malware, also known Cornhusker or Torsploit malware, to unmask Tor users.
http://securityaffairs.co/wordpress/46791/cyber-crime/former-tor-develop...
http://www.dailydot.com/politics/government-contractor-tor-malware/