What Can Make a Search Warrant Invalid?

The Fourth Amendment requires that warrants be issued only "upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized." Each of those words is a possible ground for challenge.

1. No probable cause

The affidavit must give the judge enough facts to believe evidence of a crime will be found in the place to be searched. Problems include:

• Bare conclusions without facts
• Stale information, such as a months-old tip about drugs
• An unreliable informant without corroboration

2. False or misleading statements

Under Franks v. Delaware, a defendant who makes a substantial showing that the officer included a false statement knowingly or with reckless disregard for the truth can get a hearing. If the remaining true information does not establish probable cause, the warrant fails. Leaving out important facts can be challenged in a similar way in many courts.

3. Lack of particularity

The warrant must describe the place and items specifically. A warrant to search "the house" for "evidence of crime" is too broad. Warrants for phones and computers are often challenged as overbroad.

4. A judge who was not neutral

Warrants must be issued by a neutral and detached magistrate, not someone tied to law enforcement.

5. Problems in execution

• Searching places or seizing items outside the warrant's scope
• Executing the warrant after it expired
• Knock-and-announce violations (though these rarely lead to suppression)
• Searching the wrong address

What happens if a warrant is invalid

The usual remedy is a motion to suppress. Under the exclusionary rule, evidence obtained through an unconstitutional search can be excluded from trial, along with evidence derived from it (Cornell LII). Without the evidence, prosecutors may have to drop or reduce charges.

The good-faith exception

In United States v. Leon, the Supreme Court held that evidence is not suppressed when officers reasonably relied on a warrant later found invalid, unless the affidavit was misleading, the judge abandoned the neutral role, the warrant was so lacking in probable cause that reliance was unreasonable, or it was facially deficient.

After a search

Get a copy of the warrant and the inventory of seized items, do not answer questions without a lawyer, and do not resist. A criminal defense lawyer can obtain the affidavit and evaluate a suppression motion.

Sources

1. Cornell Law School LII: Fourth Amendment
2. Cornell Law School LII: Franks v. Delaware, 438 U.S. 154 (1978)
3. Cornell Law School LII: United States v. Leon, 468 U.S. 897 (1984)
4. Cornell Law School LII: Exclusionary rule