An accessory after the fact is a person who (1) assists someone who has committed a crime, (2) after the commission of the crime, (3) with knowledge that the person committed the crime, and (4) with the intent to help the person who committed the crime avoid arrest or punishment. The United States Code defines an accessory after the fact has someone who knows a crime has been committed and receives the offender (harbors them), or relieves, comforts, or assists the offender in order to hinder or prevent the offender’s apprehension, trial, or punishment.

An accessory after the fact is different that an accomplice to a crime, who helps with the commission of the crime. An accessory after the fact is treated as a criminal offense separate from the criminal offense of the offender being assisted, and may be prosecuted as the criminal offense of obstruction of justice.

In Missouri, an accessory after the fact is someone who assists a criminal after the commission of a crime, knowing that the person has committed the crime, with the intention to help them evade arrest or punishment. This is distinct from being an accomplice, who is someone involved in the commission of the crime itself. Missouri law, under Section 562.036 of the Missouri Revised Statutes, addresses the issue of hindering prosecution, which is a similar concept to being an accessory after the fact. A person commits the crime of hindering prosecution if, with the purpose to prevent the apprehension, prosecution, conviction, or punishment of another for conduct constituting a crime, they harbor or conceal the person, provide the person with a weapon, transportation, disguise, or other means of avoiding arrest or effecting escape, or warns the person of impending discovery or apprehension. The penalties for being an accessory after the fact vary depending on the severity of the original crime committed by the principal offender. At the federal level, Title 18 of the United States Code, Section 3, defines an accessory after the fact and outlines the potential penalties, which may include fines and imprisonment. The federal statute applies when the underlying criminal act is a federal offense.