Criminal Defense Lawyers

What constitutes probable cause for obtaining a federal search warrant?

What is Probable Cause?

Probable cause is the legal standard that law enforcement must meet before they can conduct searches or make arrests. It’s basically a requirement that police have enough evidence to reasonably believe that a crime has occurred or is about to occur, and that evidence of that crime will be found through a search¹.
So probable cause is more than just a hunch or suspicion – there has to be some solid facts or evidence that point to criminal activity. But it’s also a lower bar than “beyond a reasonable doubt,” which is the very high standard used in criminal trials.

When is a Search Warrant Needed?

The 4th Amendment generally requires police to get a search warrant from a judge before they can search someone’s property or make an arrest inside a home. There’s a few exceptions – like if they have consent or see something illegal in “plain view.”
But otherwise they need to convince a judge that there’s probable cause a crime occurred and evidence will be found by searching. The judge has to agree before issuing a warrant allowing police to search or make an arrest.

What’s Required for a Federal Search Warrant?

There’s rules in the 4th Amendment and federal laws about what needs to be in a search warrant application². Here’s the basics:

• A written and sworn statement explaining the probable cause
• What locations will be searched
• What items police are looking for
• Who will do the search

The sworn statement is usually an affidavit from the lead investigator. He explains the evidence for probable cause in detail so the judge can evaluate if it’s enough to justify approving the warrant.

What Kind of Evidence Establishes Probable Cause?

There’s all kinds of evidence that could establish probable cause, depending on the type of crime. Some common examples include:

• Eyewitness statements
• Security camera footage
• Physical evidence from a crime scene
• Records showing suspicious purchases or activities
• Information from confidential informants
• Background check results on a suspect
• Surveillance observations by police

The investigator needs to lay out the evidence clearly in the affidavit. Like if an eyewitness identified the suspect, explain when and how the ID happened. Or if there’s records showing the suspect bought supplies to make bombs, describe what was purchased and when³.
The key is including enough details so the judge understands why police have good reason to think evidence of a specific crime will be found in the locations requested to be searched.

When is an Anonymous Tip Enough?

Tips from anonymous or confidential informants can establish probable cause if certain conditions are met. The tip alone isn’t enough – police need to independently investigate and confirm details to determine the tip’s reliability⁴.
For example, if an anonymous caller says John is selling drugs out of his home, police would need to stake out John’s house and observe activity consistent with drug deals before asking for a search warrant. Or interview others who confirm seeing short visits made to John’s home.
The affidavit would explain how police corroborated the tip, so the judge can review if the totality of evidence meets the probable cause standard.

Common Defenses Against Search Warrants

Defense lawyers often scrutinize search warrant applications looking for flaws when representing clients charged with crimes. Some common arguments made to suppress evidence from disputed searches include:

• The affidavit lacked probable cause – Like the evidence presented was unreliable or there wasn’t enough to justify the search.
• Evidence was obtained illegally – Like an anonymous tip that wasn’t corroborated or through general rummaging.
• Technical errors – Such as the warrant not being properly signed or listing the wrong dates or addresses.
• Omissions or falsehoods – Like important case details being left out or incorrect statements made, whether intentional or not.

While technical defects can sometimes result in suppression, judges mainly evaluate if the totality of circumstances clearly established probable cause⁵.
Having specific evidence that a particular crime occurred and that evidence will likely be recovered from the requested search locations is key. The better the probable cause presentation in the affidavit, the less likely a search warrant will be successfully challenged later.

Conclusion

Police have to follow important rules when applying for search warrants, given the 4th Amendment’s protection against unreasonable searches. Probable cause that a crime took place has to be clearly laid out through reliable evidence in order for a federal judge to authorize a search.
Defense lawyers look closely for deficiencies in probable cause or technical errors when representing clients in criminal cases. Investigators therefore need to be meticulous when preparing search warrant applications and not omit important details. Getting search warrants right is crucial for building strong cases as well as upholding constitutional rights!

<sup>1. https://www.law.cornell.edu/wex/probable_cause [return to article]
2. https://statutes.capitol.texas.gov/Docs/CR/htm/CR.18.htm [return to article]
3. https://law.justia.com/constitution/us/amendment-04/08-probable-cause.html [return to article]
4. https://www.uscourts.gov/about-federal-courts/educational-resources/about-educational-outreach/activity-resources/what-does-0 [return to article]
5. https://www.tdcaa.com/journal/warrantless-search-and-seizure/ [return to article]</sup>