http://en.wikipedia.org/wiki/Accomplice
At law, an accomplice is a person who actively participates in the commission of a crime, even though they take no part in the actual criminal offence. For example, in a bank robbery, the person who points the gun at the teller and asks for the money is guilty of armed robbery. However, anyone else directly involved in the commission of the crime, such as the lookout, a second gunman, or the getaway car driver, is an accomplice, even though in the absence of an underlying offence keeping a lookout, holding a gun, or driving a car would not be an offence.
An accomplice differs from an accessory in that an accomplice is present at the actual crime, and could be prosecuted even if the main criminal is not charged or convicted. An accessory is generally not present at the actual crime, and may be subject to lesser penalties than an accomplice or principal.
In older sources, an accomplice was often referred to as an abettor. This term is not in active use, having been replaced by accomplice.
At law, an accomplice has the same degree of guilt as the person he or she is assisting, is subject to prosecution for the same crime, and faces the same criminal penalties. As such, the three accomplices to the bank robbery above can also be found guilty of armed robbery even though only one stole the money.
http://en.wikipedia.org/wiki/Aggravating_circumstance
Aggravation is a legal concept, which Black's Law Dictionary defines as: "Any circumstance attending the commission of a crime or tort which increases its guilt or enormity or adds to its injurious consequences, but which is above and beyond the essential constituents of the crime or tort itself." For example, aggravated assault is usually differentiated from simple assault by the offender's intent (i.e., to murder, to rape etc.), the extent of the injury to the victim, or the use of a deadly weapon. An aggravating circumstance is a kind of attendant circumstance and the opposite of an extenuating or mitigating circumstance, which decreases guilt.
