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 Oklahoma, an accessory after the fact is defined under state law as someone who, knowing a crime has been committed, helps the offender with the intention of hindering or preventing the offender's arrest, trial, or punishment. This assistance can include harboring the offender, providing comfort, or any other form of assistance. This is distinct from being an accomplice, which refers to someone who assists in the commission of the crime itself. Being an accessory after the fact is a separate criminal offense and can be prosecuted under state statutes related to obstruction of justice. The specific penalties and charges can vary depending on the nature of the underlying crime and the degree of assistance provided to the offender. It's important to note that federal law also addresses accessories after the fact, and depending on the circumstances, a person could be charged under federal law as well.