A search warrant does not automatically make a government search constitutional.
Before issuing a search warrant, a judge must determine that there is probable cause to believe evidence of a crime will be found in the particular place to be searched.
That determination is ordinarily based on a sworn search-warrant affidavit submitted by law enforcement.
In federal criminal cases, defense counsel should carefully examine that affidavit. Important questions include whether the information was reliable, whether it was stale, whether there was a sufficient connection between the suspected crime and the place searched, and whether the officer omitted or misstated important facts.
Even when the affidavit fails to establish probable cause, another issue may arise: whether the government can nevertheless use the evidence under the Leon good-faith exception.
These issues can determine whether evidence seized from a home, business, vehicle, computer, or cellphone is admissible at trial.
Federal criminal defense attorney Michael J. Petro has more than 35 years of experience representing individuals in federal criminal investigations and prosecutions involving search warrants, electronic evidence, government investigations, and motions to suppress.
The Fourth Amendment Requires Probable Cause
The Fourth Amendment protects against unreasonable searches and seizures and provides that warrants may issue only upon probable cause, supported by oath or affirmation, and must particularly describe the place to be searched and the persons or things to be seized.
This creates several constitutional requirements.
A valid warrant generally must:
- Be issued by a neutral and detached judicial officer;
- Be supported by probable cause;
- Particularly describe the place to be searched; and
- Particularly describe the persons or things to be seized.
A defect in any of these areas can potentially create a Fourth Amendment issue.
What Is Probable Cause for a Search Warrant?
Probable cause is a practical, common-sense standard.
The Supreme Court’s leading decision is Illinois v. Gates, 462 U.S. 213 (1983).
Under Gates, the issuing judge examines the totality of the circumstances presented in the affidavit and determines whether there is a fair probability that contraband or evidence of a crime will be found in a particular place.
Probable cause does not require proof beyond a reasonable doubt.
It does not even require proof that it is more likely than not that evidence will be found.
But the government must provide enough facts to establish more than mere suspicion.
Courts Examine the Totality of the Circumstances
There is no mechanical formula for probable cause.
Courts consider the affidavit as a whole.
Relevant circumstances can include:
- What officers personally observed;
- Information supplied by witnesses;
- Information from confidential informants;
- Controlled purchases;
- Surveillance;
- Recorded communications;
- Financial records;
- Telephone records;
- Location information;
- Information obtained from other officers;
- The suspect’s conduct;
- The nature of the alleged crime; and
- The relationship between the alleged criminal activity and the location to be searched.
The strength of one fact may compensate for weakness in another.
That is why Gates describes the inquiry as a totality-of-the-circumstances analysis.
Probable Cause Must Connect the Evidence to the Place Searched
One of the most important requirements is often referred to as the nexus requirement.
It is not enough for the government to establish probable cause that a person committed a crime.
The affidavit must also provide a sufficient reason to believe that evidence of that crime will be found at the particular place the government wants to search.
Those are separate propositions.
For example, evidence establishing that someone sells drugs does not automatically establish that evidence of drug trafficking will be found inside every property associated with that person.
The affidavit must establish a sufficient connection between:
the crime, the evidence sought, and the location to be searched.
The Nexus Requirement Can Be Critical When Searching a Home
Homes receive the highest level of Fourth Amendment protection.
Suppose investigators establish strong evidence that a defendant committed a financial crime at work.
They then seek a warrant for the defendant’s home.
The affidavit should provide a factual basis for believing evidence of the financial crime will be found at the residence.
The government may rely on reasonable inferences depending upon the nature of the evidence and offense.
But probable cause to believe a person committed a crime does not automatically create unlimited authority to search the person’s home.
Defense counsel should identify exactly what facts supposedly connect the residence to the evidence sought.
A Search-Warrant Affidavit Must Contain Facts, Not Mere Conclusions
An affidavit cannot simply announce:
“I believe evidence of a crime will be found at the residence.”
The issuing judge must have facts from which to make an independent probable-cause determination.
Similarly, conclusory statements such as:
“The defendant is known to be a drug dealer”
or
“Based on my experience, criminals keep evidence at home”
should be examined carefully.
An officer’s training and experience can be relevant.
But the Fourth Amendment requires a judicial determination of probable cause, not merely acceptance of an officer’s conclusion.
Informant Reliability Can Be Important
Search warrants frequently rely on information provided by confidential informants or cooperating witnesses.
Under Gates, courts evaluate informant information under the totality of the circumstances rather than applying a rigid test.
Relevant considerations can include:
- Whether the informant has provided reliable information previously;
- Whether the information was based on firsthand knowledge;
- The amount of detail provided;
- Whether police independently corroborated the information;
- Whether the informant made statements against penal interest;
- Whether the informant participated in a controlled purchase; and
- Whether other evidence confirmed significant parts of the account.
An anonymous tip with little corroboration presents a different probable-cause question from detailed firsthand information supplied by a proven informant.
Controlled Drug Purchases Can Establish Probable Cause
In federal drug investigations, officers frequently use confidential informants to conduct controlled purchases.
A typical controlled buy may involve:
- Searching the informant before the transaction;
- Providing recorded government funds;
- Monitoring the informant;
- Observing the informant enter and leave a location;
- Recovering suspected drugs afterward; and
- Testing the substance.
A properly conducted controlled purchase can provide powerful probable-cause evidence.
But defense counsel should examine what actually occurred.
Did officers continuously observe the informant?
Was the informant searched adequately?
Did the informant visit another location?
Was the transaction recorded?
Did officers actually see the defendant?
Did the substance test positive?
The phrase “controlled buy” should not substitute for examining the underlying facts.
Stale Information Can Undermine Probable Cause
Probable cause must exist when the warrant is issued.
Information can therefore become stale.
There is no universal rule that information becomes stale after a particular number of hours, days, or weeks.
Courts consider the nature of the crime and the evidence sought.
A report that drugs were seen at a location months earlier may have limited value if the alleged conduct was an isolated transaction.
But older information may remain relevant when the affidavit describes:
- An ongoing conspiracy;
- Continuing fraud;
- Long-term drug trafficking;
- Records normally retained for substantial periods;
- Digital evidence;
- Child sexual abuse material; or
- Other continuing criminal activity.
The staleness analysis is therefore highly fact-specific.
The Type of Evidence Sought Matters
Different kinds of evidence have different expected lifespans.
Drugs may be sold or moved quickly.
Business records may remain for years.
Digital evidence may remain on devices even after a user attempts to delete it.
Firearms and other durable objects may remain in a person’s possession for extended periods.
The court should therefore consider both when the information was obtained and what type of evidence officers expected to find.
United States v. Aleshire
The original version of this article discussed United States v. Aleshire, 787 F. 3d 1178 (7th Cir. 2015), a Seventh Circuit decision involving probable cause for a search warrant.
The case illustrates an important general principle concerning appellate review of warrants.
Courts do not review the issuing judge’s probable-cause determination from scratch.
Instead, reviewing courts generally give substantial deference to the issuing judge’s determination that probable cause existed.
The question is whether the judge had a substantial basis for concluding that probable cause existed.
That deferential standard makes the search-warrant affidavit itself particularly important.
Courts Give Deference to the Issuing Judge
The Supreme Court has emphasized that reviewing courts should give considerable deference to a judge’s decision to issue a warrant.
There is an important institutional reason for this rule.
The Fourth Amendment generally requires officers to obtain a warrant before conducting a search.
Courts therefore do not want to discourage police from seeking judicial authorization by subjecting warrant determinations to unnecessarily technical review.
But deference has limits.
A warrant still requires an adequate factual basis.
Judicial approval does not transform an affidavit lacking probable cause into a constitutionally sufficient one.
The Court Generally Reviews What Was Presented to the Issuing Judge
When evaluating whether a warrant was supported by probable cause, the focus generally is on the information presented to the judge who issued the warrant.
The government ordinarily cannot cure a deficient affidavit after the search simply by identifying additional facts that officers knew but failed to present to the issuing judge.
This makes the wording of the affidavit critically important.
Defense counsel should compare the affidavit with:
- Police reports;
- Agent reports;
- Surveillance records;
- Body-camera recordings;
- Informant files where discoverable;
- Recorded interviews;
- Grand jury evidence where available; and
- Other discovery.
Differences can reveal important suppression issues.
False Statements Can Create a Franks Issue
A search warrant presents a different constitutional problem when the affidavit contains deliberately or recklessly false information.
The Supreme Court addressed this issue in Franks v. Delaware, 438 U.S. 154 (1978).
Under Franks, a defendant may, under appropriate circumstances, challenge the truthfulness of factual statements used to obtain a search warrant.
But obtaining a Franks hearing requires more than simply asserting that the affidavit was wrong.
The defense generally must make a substantial preliminary showing concerning the challenged statement and its significance to probable cause.
Material Omissions Can Also Matter
A Franks issue is not necessarily limited to affirmative falsehoods.
Material omissions can also create constitutional problems when an officer deliberately or recklessly leaves out information that is important to the probable-cause determination.
Suppose an affidavit tells the judge:
“A confidential informant identified the defendant as the drug supplier.”
But the affidavit omits that the informant had repeatedly given contradictory accounts or that objective evidence directly undermined the accusation.
Whether that omission warrants relief depends upon the governing legal standards and the significance of the omitted information.
The defense should therefore ask not only:
“What did the affidavit say?”
but also:
“What important information did the affidavit leave out?”
Materiality Is Critical in a Franks Challenge
Not every inaccurate statement invalidates a warrant.
The challenged information must matter.
Courts generally examine probable cause after correcting the alleged defect.
When a statement is false, the court considers the affidavit without the improperly included information.
For a material omission, the court considers the effect of including the omitted information.
If probable cause still exists after the affidavit is corrected, the defect may not justify suppression.
This is why a strong Franks challenge should identify both the falsehood or omission and its effect on probable cause.
Boilerplate Language Deserves Careful Scrutiny
Search-warrant affidavits frequently contain paragraphs based on an officer’s training and experience.
For example:
“Drug traffickers commonly maintain records of their transactions at their residences.”
Or:
“Individuals involved in fraud commonly retain electronic evidence on computers and cellular telephones.”
Such statements may be relevant.
But generalized boilerplate should not automatically substitute for facts connecting the particular defendant, crime, evidence, and place to be searched.
The defense should distinguish between:
generalized assumptions about criminals
and
particularized facts about this investigation.
Cellphone Search Warrants Require Particularity
Modern criminal investigations frequently involve warrants for smartphones.
A cellphone can contain enormous amounts of personal information:
- Text messages;
- Emails;
- Photographs;
- Videos;
- Location history;
- Internet searches;
- Financial information;
- Contacts;
- Notes;
- Applications; and
- Cloud-account data.
The Supreme Court recognized the extraordinary privacy interests implicated by modern cellphones in Riley v. California, 573 U.S. 373 (2014).
A warrant authorizing the search of a phone should therefore be examined carefully for probable cause, nexus, and particularity.
Probable Cause to Seize a Phone Is Not Always Probable Cause to Search Everything on It
This distinction can be important.
The fact that police lawfully possess a cellphone does not necessarily authorize them to search all of its digital contents.
The government generally needs a warrant or a recognized exception to the warrant requirement.
And the warrant itself should establish a sufficient connection between the alleged crime and the categories of digital evidence the government seeks.
Defense counsel should examine whether the affidavit explains why evidence of the particular offense would reasonably be found on the device.
Computer Warrants Can Present Similar Problems
Computers and digital storage devices can contain years of personal information unrelated to the alleged crime.
A warrant should not become a general license to search every digital file merely because investigators suspect some relevant evidence may exist.
Important questions can include:
- What crime was under investigation?
- What evidence was sought?
- What devices were authorized for search?
- What categories of information were specified?
- What time period was relevant?
- Was there probable cause connecting the device to the offense?
- Did investigators remain within the scope of the warrant?
Digital searches can create both probable-cause and particularity issues.
Particularity Is Separate From Probable Cause
A warrant can be supported by probable cause and still present a Fourth Amendment problem if it fails to describe sufficiently what officers may search or seize.
The Fourth Amendment specifically requires particularity.
This requirement guards against general warrants that give officers unrestricted discretion to search for anything they choose.
Defense counsel should therefore examine:
Was there probable cause?
and separately:
Was the warrant sufficiently particular?
These are related but distinct constitutional requirements.
Officers Must Stay Within the Scope of the Warrant
Even a valid warrant does not necessarily authorize every search officers conduct once they enter a property.
The scope depends upon what the warrant authorizes officers to search for.
If officers are looking for a stolen automobile, they cannot search a desk drawer because an automobile cannot be concealed there.
If they are authorized to search for small documents or digital storage devices, considerably more locations may reasonably be searched.
The nature of the items described in the warrant therefore helps define the permissible scope of the search.
The Leon Good-Faith Exception Can Save a Defective Warrant
Finding that a warrant lacked probable cause does not always result in suppression.
The Supreme Court’s decision in United States v. Leon, 468 U.S. 897 (1984) established what is commonly called the good-faith exception.
Under Leon, evidence may remain admissible when officers reasonably relied on a search warrant later found invalid.
The rationale is tied to the purpose of the exclusionary rule: deterring police misconduct.
When officers reasonably rely upon a judge’s warrant, suppression may provide little deterrent benefit.
Leon Has Important Limits
The good-faith exception is not unlimited.
Leon identified circumstances in which reliance on a warrant may not be objectively reasonable.
These include situations involving:
- An issuing judge who abandoned the neutral judicial role;
- An affidavit containing information the affiant knew was false or would have known was false except for reckless disregard of the truth;
- An affidavit so lacking in indicia of probable cause that official reliance was unreasonable; or
- A warrant so facially deficient that officers could not reasonably presume it valid.
Therefore, a defense challenge should not necessarily end after establishing a probable-cause defect.
The next question is whether Leon applies.
A Bare-Bones Affidavit Can Defeat Good Faith
An affidavit may be so deficient that no objectively reasonable officer could rely upon it.
This is sometimes described as a bare-bones affidavit.
For example, an affidavit containing little more than unsupported conclusions may fail not only the probable-cause requirement but also the government’s attempt to invoke Leon.
The distinction matters because the standards are not identical.
A court might determine that an affidavit falls short of probable cause yet still contains sufficient factual support to render an officer’s reliance reasonable.
Defense counsel therefore should address both issues separately.
The Officer Who Prepared the Affidavit Matters
Good-faith analysis can become particularly important when the officer executing the warrant is also the officer who prepared the deficient affidavit.
The government may argue that the officer reasonably relied upon the issuing judge’s approval.
The defense may respond that an officer cannot reasonably rely on judicial approval when the officer knew the affidavit omitted critical facts, contained false information, or was obviously deficient.
The precise circumstances matter.
Search-Warrant Challenges Require the Entire Timeline
A proper suppression analysis often requires reconstructing the investigation chronologically.
Defense counsel should determine:
- When investigators first received information;
- Who provided it;
- What police did to corroborate it;
- When surveillance occurred;
- When alleged criminal activity occurred;
- When the affidavit was prepared;
- When the warrant was issued;
- When the warrant was executed;
- What officers searched; and
- What they seized.
A timeline can expose staleness, factual inconsistencies, missing corroboration, and other problems that are difficult to see when reading the affidavit alone.
Read the Entire Search Warrant
Defense counsel should obtain and examine:
- The warrant application;
- The affidavit;
- The signed warrant;
- Attachments;
- Incorporated exhibits;
- The return;
- Inventory of property seized;
- Photographs;
- Search-team reports; and
- Digital forensic reports.
A constitutional challenge cannot always be evaluated by reading only the warrant’s first page.
Important limitations—or important defects—may appear in attachments.
Compare the Affidavit With the Discovery
One of the most useful defense techniques is comparing the warrant affidavit with the government’s later discovery.
Look for discrepancies.
Did the affidavit describe an informant differently from later reports?
Did surveillance actually corroborate what the affidavit claimed?
Were dates accurate?
Were statements quoted accurately?
Did the officer omit information inconsistent with probable cause?
Did the government discover facts after the search that it now improperly uses to justify the warrant?
The affidavit should be tested against the underlying investigation.
Evidence Found During the Search Cannot Retroactively Establish Probable Cause
A successful search does not prove that probable cause existed beforehand.
Suppose officers search a home and discover drugs, firearms, and large quantities of cash.
Those discoveries may provide overwhelming evidence of criminal activity.
But they cannot retroactively establish probable cause for the warrant.
The Fourth Amendment question is whether sufficient probable cause existed before the search occurred, based on the information properly presented to the issuing judge.
The government cannot justify a search by pointing to what the search happened to uncover.
A Warrant Is Not the End of the Fourth Amendment Analysis
When clients learn that police obtained a warrant, they sometimes assume there is nothing to challenge.
That is incorrect.
A warrant changes the legal analysis, but it does not end it.
Defense counsel should examine:
- Probable cause;
- Nexus;
- Staleness;
- Informant reliability;
- False statements;
- Material omissions;
- Particularity;
- Scope;
- Execution of the warrant; and
- The Leon good-faith exception.
Depending upon the facts, one or more of these issues may support a motion to suppress.
The Government Bears Important Evidentiary Responsibilities
Search-warrant litigation is fact intensive.
The government may rely heavily upon the presumption that officers acted pursuant to judicial authorization.
But the defense is entitled to examine whether the constitutional requirements supporting that authorization were actually satisfied.
A warrant should not be treated as an evidentiary shortcut that eliminates meaningful Fourth Amendment review.
The Lesson From Search-Warrant Cases
The central question is not simply:
“Did police have a warrant?”
The proper questions include:
What facts were presented to the issuing judge?
Did those facts establish a fair probability that evidence would be found at the particular location?
Was the information current enough to support probable cause?
Was the warrant sufficiently particular?
Were material facts misstated or omitted?
Did officers remain within the warrant’s scope?
And if the warrant was defective, can the government establish objectively reasonable reliance under Leon?
Those questions can determine whether evidence obtained during a government search is admissible in a federal criminal prosecution.
Experienced Federal Search Warrant Attorney
Michael J. Petro has more than 35 years of criminal defense experience representing individuals in federal criminal investigations and prosecutions.
Search warrants frequently play a central role in federal drug, fraud, firearm, public-corruption, computer, and other criminal investigations.
Defense counsel should obtain the warrant and affidavit, reconstruct the government’s investigation, identify the claimed nexus between the crime and the location searched, examine the reliability and age of the information, and determine whether the warrant satisfied the Fourth Amendment.
If you are facing federal criminal charges arising from a search warrant, home search, cellphone search, computer search, or seizure of evidence, contact federal criminal defense attorney Michael J. Petro to discuss whether the government’s search can be challenged.