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 Wisconsin, an accessory after the fact is someone who assists another person who has committed a crime, knowing that the person has committed the crime, with the intention to help them avoid arrest or punishment. This assistance can include actions such as harboring the offender, providing comfort, or any other form of assistance that could hinder the offender's apprehension, trial, or punishment. Being an accessory after the fact is distinct from being an accomplice, as the latter involves aiding in the commission of the crime itself. In Wisconsin, being an accessory after the fact is a separate criminal offense and can be prosecuted under the statutes related to obstruction of justice. The specific charges and penalties can vary based on the nature of the underlying crime and the extent of the assistance provided to the offender.