Criminal Laws: Mistake of Fact Defense

A “mistake of fact” is a common justification defense used to challenge criminal charges.   It means that a violation of the law occurred, but only as a result of a mistaken fact.

For example, let’s say a person is on a business, and must rent a vehicle.  They then have to use valet parking for their business meeting.  At the end of the day, the valet parking attendant, inadvertently mixes up the keys, and brings you someone else’s white car, same make, model and year.  You drive the car away.  The next morning, you are contacted by police for questioning in the theft of the real owner’s vehicle.  You did not know the valet brought you the wrong vehicle; and you did not intend to permanently deprive” the real owner of their vehicle.

Therefore, in the event of charges brought against the store owner, the “mistake of fact” would be a justifiable defense.

Arizona Criminal Law – Ignorance or Mistake of Fact Relieves Criminal Liability

A.R.S. 13-204 describes the “Effect of ignorance or mistake upon criminal liability”. It means that “ignorance or mistaken belief” of a fact may relieve a person of criminal relieves a person from criminal liability only if:

• Because of an honest mistaken of fact (s), a defendant lacked a state of mind as to willful, knowledge, and intent of violating the law which is required to pursue conviction;

• The mistaken fact was material and supports a justification defense as outlined chapter in 4 of Title 13.

So to utilize this defense the most effectively, the mistake of fact must be honest, material, and justifiable.