1. Perpetrator
- the one who commits crime or offense.
- is the robber, assailant, counterfeiter, etc. -the person who actually committed the crime. The distinction between suspect and perpetrator recognizes that the suspect is not known to have committed the offense, while the perpetrator [who may not be a suspect yet] is the one who actually did. The suspect may be a different person from the perpetrator, or there may have been no actual crime, which would mean there is no perpetrator.
http://www.allwords.com/word-perpetrator.html
2. Cyber Criminal
- First it is important to understand what cyber crime is. Cyber crime is a crime committed online via emails, or chatrooms or any other form of interaction that can take place online. It does not vary much from the same criminal misconducts committed in real life. The only difference is the fact that it is much harder to pursue these types of criminals, because they transcend the typical borders associated with countries and the jurisdictions of various law enforcement agencies may clash as a result.

Cybercrime can take the form of cyber stalking, where they follow you around into various chat rooms and harass you online. This can also be things like a hacker taking control of your computer or someone stealing your identity online. Everything can be destroyed by cyber criminals. They can wipe entire hard drives, steal your entire life and everything about it and essentially just mess with your entire world.
http://www.articlesbase.com/internet-articles/cyber-crime-cyber-criminals-and-prevention-575109.html

3. Cyber Terrorist
- hacker: a programmer who breaks into computer systems in order to steal or change or destroy information as a form of cyber-terrorism.
http://wordnetweb.princeton.edu/perl/webwn?s=cyber-terrorist