"Perpetrator"
Per"pe*tra`tor\, n. [L.]

1. One who perpetrates; esp., one who commits an offense or crime.
2. To be responsible for; commit: perpetrate a crime; perpetrate a practical joke.

http://dictionary.reference.com/browse/perpetrator

"Cyber Terrorism"

Cyberterrorism is a controversial term. Some authors choose a very narrow definition, relating to deployments, by known terrorist organizations, of disruption attacks against information systems for the primary purpose of creating alarm and panic. By this narrow definition, it is difficult to identify any instances of cyberterrorism. Cyberterrorism can also be defined much more generally, for example, as “The premeditated use of disruptive activities, or the threat thereof, against computers and/or networks, with the intention to cause harm or further social, ideological, religious, political or similar objectives. Or to intimidate any person in furtherance of such objectives.” This broad definition was created by Kevin G. Coleman of the Technolytics Institute.^[1] The term was coined by Barry C. Collin.

http://en.wikipedia.org/wiki/Cyber-terrorism

"Cyber Criminals"

Any use of a computer as an instrument to further illegal ends, such as committing fraud, trafficking in child pornography and intellectual property, stealing identities, or violating privacy. Cybercrime, especially through the Internet, has grown in importance as the computer has become central to commerce, entertainment, and government. The international nature of cybercrimes has led to international cyberlaws.

http://encyclopedia2.thefreedictionary.com/cybercriminals