What Is an Affidavit: A Written Statement Made Under Oath

What an Affidavit Is

An affidavit is a written statement of facts that the person making it swears or affirms is true. At a concept level, it is a way of putting someone’s account on paper under oath, so that the statement carries the weight and the responsibility that come with testifying, even though it is written rather than spoken in a courtroom.

The person who makes the affidavit is generally called the affiant. What separates an affidavit from an ordinary letter or note is the oath or affirmation behind it, the formal commitment that the contents are true. How affidavits are formatted and handled tends to vary by jurisdiction.

How Affidavits Are Used in Criminal Procedure

Affidavits show up at several points in a criminal case, often as a way of presenting facts to a court in writing. Knowing where they appear helps explain why the word comes up so often:

• Warrant applications. A request for a warrant is frequently supported by an affidavit setting out the facts a judge or magistrate reviews before deciding whether to issue it.
• Supporting motions. A written motion is sometimes accompanied by an affidavit that provides the sworn factual basis for what the motion asks.
• Establishing facts. An affidavit can put a particular set of facts before a court in writing, which the court may weigh alongside other materials.

What Makes One Legally Meaningful

Not every written statement carries the weight of an affidavit. A few features tend to be what gives one its legal significance, and they are worth understanding at a concept level:

• An oath or affirmation. The affiant generally commits, formally, that the statement is true.
• Personal knowledge. Affidavits are generally expected to rest on what the affiant actually knows, rather than on guesswork or rumor.
• Proper execution. Many jurisdictions require the affidavit to be signed and, where applicable, notarized or sworn before an authorized official.

The Consequences of False Statements

Because an affidavit is made under oath, the law generally treats a knowingly false statement in one as a serious matter. At a concept level, swearing to something that the affiant knows is untrue can expose that person to separate legal consequences, since the whole point of the oath is that the court can rely on what was said.

The specific labels and procedures attached to false sworn statements vary by jurisdiction, and what is described here is the general principle rather than the rule in any one place. The takeaway many people draw is simply that an affidavit is not a casual document, and that the oath behind it is meant to carry real weight.

How Affidavits Can Be Contested

Because so much can rest on what an affidavit says, its accuracy or completeness is something that can be questioned. One avenue people ask about is challenging whether the statements in an affidavit supporting a warrant were accurate or were missing important facts, which, depending on the situation, can affect how a court views the action the affidavit supported.

Whether such a challenge fits a given case depends on the facts and the law of the jurisdiction. The related guides on search warrants and on probable cause describe the proceedings where affidavits are often examined. What is described here is the general shape of the document, not the rule in any one court.

Questions to Explore About an Affidavit

Questions that move past the label and toward what applies to a specific situation:

• Who made the affidavit, and was it based on their personal knowledge?
• What action does the affidavit support, a warrant, a motion, or something else?
• Was it properly sworn and, where required, notarized or executed before an authorized official?
• Are the facts in the affidavit accurate and complete, or is there something to question?