Criminal Law


Accomplice liability makes one who assists or encourages a criminal to facilitate a crime criminally liable for the crime himself.

The amount of assistance is immaterial; just some amount of assistance is required.

At common law, one could be an accessory after the fact and thereby by convicted of a crime committed by one he helped after the crime was committed. The modern approach however is to make this a separate offense with a much lower penalty.

Merely being present is usually not enough to qualify as encouragement. Rare exceptions exist however. In addition, one may be liable for the crime if he has a preexisting duty to the victim.

While causation is generally required at common law, acts that merely "raise the chance" of harm are sufficient for liability. Many jurisdictions and the Model Penal Code reject the causation requirement altogether and allow liability even when the actor's attempt to aid the principal was ineffective.

Accomplice liability's mens rea requirements are that the defendant must both have the intent to assist the primary party in the conduct that forms the basis of the offense as well as the mental state required for commission of the offense aided.

Some jurisdictions require that the act be performed with the purpose of facilitating the crime, but others only require the knowledge that it would.

Most jurisdictions extend accomplice liability to any other offense that was a natural and probable consequence of the crime aided.

Natural and Probable Consequence

The natural and probable consequences doctrine allows for liability for offenses other than those known to the accomplice.

Under this doctrine, each person is responsible for everything done by his confederates which is the probable and natural consequence of the wrongful act specifically agreed on. The connection between the acts must be reasonably apparent. An unplanned act cannot be a fresh and independent product of the mind of one of the confederates outside of, or foreign to, the common design.

Many jurisdictions and the Model Penal Code reject the doctrine.

Innocent Instrumentality

The innocent instrumentality rule says that one who effects a criminal act through an innocent or unwitting agent (the innocent instrumentality) is a principal in the first degree.

Conspiracy v. Complicity

Although usually an accomplice is a conspirator, conspiracy differs from accomplice liability in several ways: