Digital Data and the Fourth Amendment Prohibition Against Illegal Search and Seizure

Defense Discovery Concerns Regarding Digital Investigations

The Fourth Amendment of the United States Constitution, ratified on December 15, 1791, establishes the protection for every U.S. citizen against unreasonable searches and seizures by the government.  It states:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Of course, back when the Bill of Rights was written, most evidence would have been physical things (like knives, guns, etc.) or documents on paper. Things have changed.  Today, more and more evidence that the government wants to use in a criminal matter is digital stuff stored in the cloud, or on a smartphone, tablet, drive, or computer.

It’s amazing to ponder how times have changed since our fundamental right against unreasonable search and seizure was formalized in the Bill of Rights.  Still, one of the beauties of our American legal system is that while technology may have advanced in ways that Thomas Jefferson and Benjamin Franklin would deem miraculous, our constitutional provisions remain steadfast.  The Fourth Amendment still retains the power to protect our rights against unreasonable governmental investigations.

Criminal defense lawyers can still rely upon the Fourth Amendment to keep illegally obtained evidence from being used against someone in a criminal case.  It’s just much more complicated with digital data.

What is Digital Data?

Digital data involves a machine language that at its core is a binary system (ones and zeros; on or off) that can be used to store all sorts of things, from basic textual communications (words, calculations) to images, videos, sound, etc.  For instance, a photograph taken with a vintage camera and processed in a dark room can be digitally transformed into pixels where thousands of “bits” each store a specific color characteristic.  These are then placed into a grid that will replicate the image that can be seen on the old photograph.  This will be a digital image that duplicates that old school photo. To learn more, read “Digital Data,” written by Margaret Rouse and published by Technopedia on August 7, 2013.

Digital data storage varies, too.  There are simple text files stored on a home computer.  There are also things like complex databases (think cloud; hierarchical; network; centralized; etc.); multimedia (linear; nonlinear; etc.), and encrypted content (symmetric key; asymmetric key). See, e.g., “What is data storage,” written by Stephanie Susnjara and Ian Smalley and published by IBM on July 15, 2024.

The Problem of Digital Data Storage

Obviously, digital data storage is a massive undertaking.  It’s huge and complex.  Physically, there are things like optical discs used by libraries to archive information on cartridges.  There are data centers.  There are secondary storage devices like hard disk drives (HDDs) and flash SSDs.  See, “Digital Storage and Memory Projections For 2025,” written by Thomas Coughlin and published by Forbes on December 11, 2024.

And once the digital storage device is accessed, it is arguably very easy to roam through all sorts of data stored there.   Therein lies the problem, from a criminal defense perspective. Why?

Digital storage in today’s world offers a great opportunity for government investigators (and prosecutors) to look at all sorts of things that if stored on paper and in physical files would not be so readily available to them.  Today’s criminal defense lawyer needs to comprehend how digital data is collected and stored in order to confirm if governmental activity exceeded the parameters of a legal search and seizure.

As one federal appellate court explained in United States v. Comprehensive Drug Testing, Inc., 621 F.3d 1162, 1175-76 (9th Cir. 2010) (Kozinski, C.J., concurring):

The problem can be stated very simply: There is no way to be sure exactly what an electronic file contains without somehow examining its contents — either by opening it and looking, using specialized forensic software, keyword searching or some other such technique. But electronic files are generally found on media that also contain thousands or millions of other files among which the sought-after data may be stored or concealed. By necessity, government efforts to locate particular files will require examining a great many other files to exclude the possibility that the sought-after data are concealed there.

Digital Search Complexities: Opening Pandora’s Box

One important consideration here, for both the prosecution and the defense, is how cumbersome these digital investigations can become.  There can literally be millions of digital files that reveal themselves once the investigator gains access to the storage.  It can take weeks or months to review it.

Picture investigators on the premises of a location (home, business) where they discover digital storage.  It is impossible for them to sit there and go through the data on these premises.  It is absolutely unsustainable to argue to any judge that an agent be allowed to conduct a digital search in someone’s home for extended periods of time.

What law enforcement has done to solve this problem is to copy contents of the digital storage device, arguing this as a legal seizure, and then take their copy back to their offices for a more leisurely stroll through its contents.  And sure, defense lawyers immediately see red flags here because this deviates significantly at the get-go from a normal, old-school search of the premises.

Picture this: in Perry Mason’s day, the police or FBI agents could look through the filing cabinet of the accused to seize only those files that pertained to their search warrant.  With digital storage, they are essentially taking a dolly and carting out the entire filing cabinet with them.

Obviously, this opens the floodgates.  Copying the digital storage means that the government now has within its possession all sorts of stuff that is blatantly outside their search warrant.  Anything from trade secrets, personnel health information, or grandmother’s secret recipe for apple pie, to all sorts of a company’s proprietary information is sitting there for viewing.  This is forehead-slapping overreaching of the parameters, protections, and intent of the Fourth Amendment.  Flies in the face of it.

AUSAs and ADAs may argue that anything found that is asserted to be evidence of the commission of a criminal act is within the “plain view” doctrine.  But it’s not that easy.

Courts and the Application of the Fourth Amendment to Digital Storage

Today, the law is still being developed on how the protections against unreasonable search and seizure applies to digital data and digital storage.  While there has been some direction by SCOTUS (see below), criminal defense lawyers around the country today are dealing with significant research time involving various opinions and rationales and perspectives from the lower appellate and district courts.

As an overview, criminal defense lawyers dealing with digital discovery in any federal or state criminal case may consider the following:

1. General searches are on their face unconstitutional.

General searches are clearly forbidden by the Fourth Amendment.  Its language is clear (emphasis added):

 “[N]o Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”

So, any grabbing of a copy of the entire contents of an accused’s digital storage is suspect at the outset.

2. Warrantless searches are presumptively unreasonable; the plain sight doctrine.

There are exigent circumstances that form exceptions to the general rule, but a clear argument here is that warrantless searches are presumed to be unreasonable and violative of the Fourth Amendment.

The defense attorney may argue either (a) there was a flat-out warrantless search; or (b) while law enforcement had a search warrant, their taking of the digital data exceeded its scope.

Either way, there is the basis to file a motion to exclude the evidence being used in the state’s case as being the result of an unconstitutional search and seizure.  The plain view doctrine will not vindicate the government’s intrusion.

From SCOTUS in Coolidge v. New Hampshire, 403 U.S. 443, 454-55 (1971) (citations omitted):

Finally, the “plain view” doctrine has been applied where a police officer is not searching for evidence against the accused, but nonetheless inadvertently comes across an incriminating object….

What the “plain view” cases have in common is that the police officer in each of them had a prior justification for an intrusion in the course of which he came inadvertently across a piece of evidence incriminating the accused. The doctrine serves to supplement the prior justification—whether it be a warrant for another object, hot pursuit, search incident to lawful arrest, or some other legitimate reason for being present unconnected with a search directed against the accused—and permits the warrantless seizure. Of course, the extension of the original justification is legitimate only where it is immediately apparent to the police that they have evidence before them; the “plain view” doctrine may not be used to extend a general exploratory search from one object to another until something incriminating at last emerge.

What is this plain view argument?  Most prosecutors understand that if there is a physical search by law enforcement, and something (say, a gun on a sofa) can be easily seen – it is in “plain view” – then it can be seized without a warrant (assuming their presence is lawful in the first place).   Trying to argue this applies to digital storage is wonky, because of the technological realities of digital storage.  Once law enforcement gets into that storage then they can literally see everything. It’s inherently different from a gun on a sofa.

3. Warrants have to be specific.

To meet the requirements of the Fourth Amendment, the search and seizure warrant has to be specific.  It must explain the search location (the house? The house and the garage?).  It must explain the items to be seized if found.

A search warrant allowing the FBI to search a doctor’s office does not immediately give them the right to drive over to his home and search there, too.  And, law enforcement cannot roam through during a search and take whatever they might want to remove.

The warrant must form a link between the item and the criminal activity that is the basis of their investigation. There must be a clear connection to the crime for which the judge found probable cause to sign the search warrant in the first place.

From SCOTUS in Illinois v. Gates, 462 U.S. 213, 238 (1983):

In evaluating whether probable cause exists, it is the task of the issuing magistrate `to make a practical, common-sense decision whether, given all the circumstances set forth in the affidavit . . . there is a fair probability that contraband or evidence of a crime will be found in a particular place.

A free-for-all search of the entirety of accessed digital storage arguably violates the specificity requirement of a search warrant under the Fourth Amendment.

4. What about third parties whose privacy may be violated by revelations in the digital storage?

Another consideration from a defense perspective, especially for clients who provide services to others (like doctors, bankers, pharmacists, etc.): what about the digital data that pertains to people other than the suspect, target, or accused?

The Fourth Amendment search and seizure protections, as well as other privacy laws and statutes, may come into play in digital storage seizures and searches.

Federal Rule of Criminal Procedure 41

To help with the discovery and admission of digital evidence, Congress has added language to Federal Rule of Criminal Procedure 41 (“FRCP 41”), which deals with search and seizure.  In its subdivision (e)(2), FRCP 41 provides (emphasis added):

(2) Contents of the Warrant.

(A) Warrant to Search for and Seize a Person or Property. Except for a tracking-device warrant, the warrant must identify the person or property to be searched, identify any person or property to be seized, and designate the magistrate judge to whom it must be returned. The warrant must command the officer to:

(i) execute the warrant within a specified time no longer than 14 days;

(ii) execute the warrant during the daytime, unless the judge for good cause expressly authorizes execution at another time; and

(iii) return the warrant to the magistrate judge designated in the warrant.

(B) Warrant Seeking Electronically Stored Information. A warrant under Rule 41(e)(2)(A) may authorize the seizure of electronic storage media or the seizure or copying of electronically stored information. Unless otherwise specified, the warrant authorizes a later review of the media or information consistent with the warrant. The time for executing the warrant in Rule 41(e)(2)(A) and (f)(1)(A) refers to the seizure or on-site copying of the media or information, and not to any later off-site copying or review.

(C) Warrant for a Tracking Device. A tracking-device warrant must identify the person or property to be tracked, designate the magistrate judge to whom it must be returned, and specify a reasonable length of time that the device may be used. The time must not exceed 45 days from the date the warrant was issued. The court may, for good cause, grant one or more extensions for a reasonable period not to exceed 45 days each. The warrant must command the officer to:

(i) complete any installation authorized by the warrant within a specified time no longer than 10 days;

(ii) perform any installation authorized by the warrant during the daytime, unless the judge for good cause expressly authorizes installation at another time; and

(iii) return the warrant to the judge designated in the warrant.

Guidance is found in the 2009 Committee Notes to this amendment:

Subdivision (e)(2). Computers and other electronic storage media commonly contain such large amounts of information that it is often impractical for law enforcement to review all of the information during execution of the warrant at the search location. This rule acknowledges the need for a two-step process: officers may seize or copy the entire storage medium and review it later to determine what electronically stored information falls within the scope of the warrant.

The term “electronically stored information” is drawn from Rule 34(a) of the Federal Rules of Civil Procedure, which states that it includes “writings, drawings, graphs, charts, photographs, sound recordings, images, and other data or data compilations stored in any medium from which information can be obtained.” The 2006 Committee Note to Rule 34(a) explains that the description is intended to cover all current types of computer-based information and to encompass future changes and developments. The same broad and flexible description is intended under Rule 41.

In addition to addressing the two-step process inherent in searches for electronically stored information, the Rule limits the 10 [14] day execution period to the actual execution of the warrant and the on-site activity. While consideration was given to a presumptive national or uniform time period within which any subsequent off-site copying or review of the media or electronically stored information would take place, the practical reality is that there is no basis for a “one size fits all” presumptive period. A substantial amount of time can be involved in the forensic imaging and review of information. This is due to the sheer size of the storage capacity of media, difficulties created by encryption and booby traps, and the workload of the computer labs. The rule does not prevent a judge from imposing a deadline for the return of the storage media or access to the electronically stored information at the time the warrant is issued. However, to arbitrarily set a presumptive time period for the return could result in frequent petitions to the court for additional time.

It was not the intent of the amendment to leave the property owner without an expectation of the timing for return of the property, excluding contraband or instrumentalities of crime, or a remedy. Current Rule 41(g) already provides a process for the “person aggrieved” to seek an order from the court for a return of the property, including storage media or electronically stored information, under reasonable circumstances.

Where the “person aggrieved” requires access to the storage media or the electronically stored information earlier than anticipated by law enforcement or ordered by the court, the court on a case by case basis can fashion an appropriate remedy, taking into account the time needed to image and search the data and any prejudice to the aggrieved party.

The amended rule does not address the specificity of description that the Fourth Amendment may require in a warrant for electronically stored information, leaving the application of this and other constitutional standards concerning both the seizure and the search to ongoing case law development.

In sum, FRCP 41(e)(2)(B) acknowledges that the quantity of digital data stored in “electronic storage media” makes it “impractical for law enforcement to review all of the information during execution of the warrant at the search location.”

Law enforcement must determine the digital data that was not within their search warrant parameters and return it.  FRCP 41 is not to be read to approve of general searches of digital storage.  However, for criminal defense lawyers there is still insufficient language here (in the rule, or the commentary) to protect against assertions of the “plain view doctrine.”

SCOTUS in Riley and Carpenter

While SCOTUS has not provided a definitive opinion on this issue, there are precedents to support defense challenges to searches and seizures of digital evidence by the government.  Two of these are Riley v. California, 573 U.S. 373, 393, 134 S.Ct. 3473 (2014) and Carpenter v. United States, 585 U.S. 296, 304, 138 S.Ct. 2206, 201 L.Ed.2d 507 (2018).

1. Riley v. California

Over a decade ago, SCOTUS held in Riley that police trying to search the contents of a cell phone obtained during an arrest, without a search warrant for that digital data, was a warrantless search in violation of the Fourth Amendment.  The arguments that this was a search incident to the arrest failed. The High Court found that the data on the phone was not a direct danger to the officer, nor did the phone’s digital storage involve potential destruction of evidence like might happen with some kinds of physical evidence.

As a result of Riley, as a general rule law enforcement has to get the approval of a judge through a valid search warrant based upon probable cause before going into a phone’s storage and accessing the data.

2. Carpenter v. United States

In 2018, SCOTUS found in Carpenter that cell-site location information from wireless carriers needs to have a search warrant supported by probable cause and signed by a judge before law enforcement can access it.  Because of the data itself, its detailed and continuous nature, there was a reasonable expectation of privacy that mandated the protections of the Fourth Amendment.

It’s narrow: things like shorter time periods than those involved with the instant case (over four months) might not have the same result.

Another concern: the purchasing of location data from brokers by governmental agencies, and how some courts are finding this is not constitutionally protected.  Read, Tokson, Matthew. “Government Purchases of Private Data.” Wake Forest L. Rev. 59 (2024): 269.

Defense Concerns in the Use of Digital Data in Criminal Prosecutions

Today, the law continues to evolve in the search and seizure of digitally stored data, just as technology keeps developing on how data is collected, used, and protected.  For instance, consider how Apple’s advancing technology in encrypted data on smartphones stumped law enforcement’s attempts to access the storage.  Details are provided in our earlier article, Privacy of Your Smart Phone: Police Search and Seizure and Apple’s Fight Against the FBI.

While SCOTUS has provided some clarity in cases like Riley and Carpenter, many other substantive search and seizure issues remain to be litigated, or have found themselves with conflicting results at the district or appellate level.  Moreover, rapidly changing digital technologies bring with them brand new considerations that may not have been previously addressed.

Digital data discovery is complex and challenging to both prosecution and defense.  It is very important for criminal defense lawyers to keep up with evolving technologies (like Apple smartphone encryption) as well as how various state and federal opinions are addressing different digital data legalities under the Fourth Amendment.

Our next article will discuss more about the admissibility of digital evidence, particularly Federal Rule of Evidence 901 and the use of social media in criminal cases.

To learn more, read:

• Why You May Need a Federal Criminal Defense Lawyer in Texas;
• The Federal Criminal Justice System: After Arrest, From Arraignment to Sentencing;
• How Arrests Happen: From Investigation to Arraignment, Being Charged for a Federal Crime;
• Encryption and Law Enforcement Investigations: Police Access to Encrypted Data; and
• Ring Cameras and Police Surveillance: Growing Police Power Privacy Concerns.

Digital data storage protections provided by the Fourth Amendment are at risk because of things like (1) the massive amount of data usually found in digital storage; (2) the unique characteristics of the digital data itself; and (3) advancing technology.  Criminal defense strategies focusing upon the constitutional rights of the accused will be faced with prosecutorial arguments about the need for law enforcement to effectively investigate in digital realities.  Zealous representation must be provided.

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For more information, check out our web resources, read Michael Lowe’s Case Results, and read “The Early Part of a Texas Criminal Case in State or Federal Court.”