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 New Hampshire, 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, and with the intent 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. New Hampshire law, under RSA 626:8, categorizes an accessory after the fact under the broader term 'accomplice' but distinguishes the roles based on the timing and nature of the assistance. The penalties for being an accessory after the fact can vary depending on the severity of the original crime but generally include fines, imprisonment, or both. This offense can also be prosecuted under federal law, particularly if the underlying crime is a federal offense, as outlined in Title 18 of the United States Code, Section 3. The federal statute specifies that an accessory after the fact can face punishment, but typically less severe than that for the principal offender. Both state and federal laws treat obstruction of justice as a serious crime, and those found guilty of being an accessory after the fact can face significant legal consequences.