Fourth Amendment

Overview
The Fourth Amendment to the U.S. Constitution provides that:


 * "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."

"The . . . constitutional prohibition against unreasonable searches and seizures, has its source in that principle of the common law which finds expression in the maxim that 'every man's house is his castle.' English history discloses [that the] . . . constitutional provisions . . . had their origin 'in the . . . unwarrantable intrusion of executive agents into the houses . . . of individuals . . . .'"

This right had a long history in English common law. Sometimes colloquially expressed as “a man’s house is his castle,” it meant that one had a right to expect that one’s home, possessions, and person were safe against arbitrary and forceful intrusion by the King’s agents. At the same time, it recognized that the lawful agents of the state can intrude on private property to execute or enforce the law, so long as they obey certain procedural rules that protect the subject of the search.

This protection was understood in 1787 to limit and regulate physical trespass, and the seizing of papers, effects, or “things.” Technology began to threaten the effectiveness of this protection about a century ago. The telegraph and telephone allowed information about oneself to be separated from person, places, paper, and objects because it could exist in the form of pulses of electricity. In 1928 (and again in 1942) the U.S. Supreme Court declared that wiretapping was not forbidden by the Fourth Amendment because there was no physical trespass and physical “papers or effects” were not seized.

Searches and Seizures
The critical triggering phrase of the fourth amendment is “searches and seizures.” If there is no search or seizure, then official behavior is not covered by the fourth amendment, and it need not be reasonable, based on probable cause, or carried out pursuant to a warrant. Although there may be statutory protections that require certain conduct, an individual does not have fourth amendment protections unless there is a search and seizure.

The U.S. Supreme Court has said that a “search” occurs where the Government infringes upon a person’s legitimate expectation of privacy, consisting of both an actual, subjective expectation of privacy as well as an objectively reasonable expectation of privacy &mdash; “i.e., one that has a source outside the Fourth Amendment, either by reference to concepts of real or personal property law or to understandings that are recognized and permitted by society.”

A “seizure” of a person occurs when a government official makes an individual reasonably believe that he or she is not at liberty to ignore the government’s presence in view of all the circumstances surrounding the incident.

Unreasonable
The secondary triggering phrase of the fourth amendment is “unreasonable.” Even if official conduct is regarded as a search or seizure, there is no invasion of fourth amendment protections if the conduct is reasonable. Determination of reasonableness depends on the judicial balancing of the individual interest, generally regarded as a privacy interest, against the governmental interest, including law and order, national security, internal security, and the proper administration of the laws. Reasonableness generally entails a predicate of probable cause and, with many exceptions, the issuance of a warrant.

Warrant Based upon Probable Cause
The U.S. Supreme Court has interpreted the Fourth Amendment to include a presumptive warrant requirement on all searches and seizures conducted by the government, and has ruled that any violations of this standard will result in the suppression of any information derived therefrom.

Generally, the same warrant rules apply when preparing and executing a search warrant for digital evidence as in other investigations. Law enforcement should consider the following when preparing and executing a search warrant for digital evidence:


 * 1. Describing property. If the evidence sought is the computer itself (and the hardware is an instrumentality, a fruit of the crime, or contraband), then the warrant should describe the computer as the target of the search. If the evidence sought is information that may be stored on digital media, then the warrant should describe what that evidence is and request the authority to seize it in whatever form (including digital) it may be stored. This includes requesting authority to search for evidence of ownership and control of the relevant data on the media.


 * 2. Conducting a search. In some cases, a search of an electronic storage device can require significant tech­nical knowledge and should be conducted by appropriate personnel who are sup­plied with a copy of the search warrant to ensure that the search is within its scope. In the course of conducting a search, law enforcement may discover passwords and keys that could facilitate access to the system and data. Law enforcement may also find evidence of a crime that is outside the scope of the search warrant. In such an event, law enforcement should consider securing another warrant to expand the scope of the search.


 * 3. Reasonable accommodations. In some cases, it might be impractical to search the device on-site. If a device is to be searched off-site, law enforcement should consider adding language to the warrant affidavit that justifies its removal. If a device is removed for an off-site search, the search should be completed in a timely manner. Law enforcement may consider returning copies of noncontraband seized data, even if they are commingled with evidence of a crime, to accommodate a reasonable request from suspects or third parties.

The U.S. Supreme Court, however, has also recognized situations that render the obtainment of a warrant impractical or against the public’s interest, and has accordingly crafted various exceptions to the warrant and probable cause requirements of the Fourth Amendment.

Warrantless searches
There are several well-recognized exceptions to securing a warrant. Although the following is not an exhaustive list, the examples provide an idea of how the common exceptions apply to the search and seizure of digital evidence.

Consent. Consent is a valuable tool for an investigator. It can come from many sources, including a log-in banner, terms-of-use agreement, or company policy. Some considerations include:


 * (1) Like a shared apartment, a computer can have multiple users. Consent by one user is always sufficient to authorize a search of that person’s private area of the computer, and in most instances is sufficient to authorize a search of the com­mon areas as well. Additional consent may be needed if law enforcement encoun­ters password-protected files. Also, a parent in most cases can consent to a search of a minor child’s computer.
 * (2) Consent can be limited by subject matter, duration, and other parameters. Consent can be withdrawn at any time.
 * (3) The general rule is that a private-sector employer can consent to a search of an employee’s workplace computer. The rules are more complicated when the employer is the government.

Exigent circumstances. To prevent the destruction of evidence, law enforcement can seize an electronic storage device. In certain cases in which there is an immediate danger of losing data, law enforcement may perform a limited search to preserve the data in its cur­rent state. Once the exigent circumstances end, so does the exception.

Search incident to arrest. The need to protect the safety of law enforcement or to preserve evidence can jus­tify a full search of an arrestee and a limited search of the arrest scene. This search incident to arrest can include a search of an electronic storage device, such as a cell phone or pager, held by the subject. Inventory search. The inventory search exception is intended to protect the property of a person in custody and guard against claims of damage or loss. This exception is untested in the courts, so it is uncertain whether the inventory search exception will allow law enforcement to access digital evidence without a warrant.

Plain view doctrine. The plain view doctrine may apply in some instances to the search for and seizure of digital evidence. For plain view to apply, law enforcement must legitimately be in the position to observe evidence, the incriminating character of which must be immediately apparent. Law enforcement officials should exercise caution when relying on the plain view doctrine in connection with digital media, as rules concerning the application of the doctrine vary among jurisdictions.

Fourth Amendment Analysis
At its broadest, a Fourth Amendment analysis is a two-stage inquiry. First, was the action of a government officer toward a person or thing sufficiently intrusive to constitute a “search” or “seizure?” Second, if a “search” or “seizure” did occur, was the intrusion “reasonable” in light of the circumstances? The “reasonableness” of a particular government action is judged by balancing the governmental interest which allegedly justifies the official intrusion against a person’s legitimate expectations of privacy. Courts must consider the scope of the particular intrusion, the manner in which it is conducted, the justification for initiating it, and the place in which it is conducted.

If a court determines that a government intrusion constitutes a “search” or “seizure” that was not reasonable in light of the relative weights of the government’s interest and a person’s constitutionally protected privacy interests, it will conclude that a Fourth Amendment violation has occurred. A violation of the Fourth Amendment may, as a general rule, result in the suppression of any information derived therefrom in a judicial proceeding.

Government Action
In most circumstances, government action is implicated when a government official conducts a search. Generally speaking, the Fourth Amendment’s limitations do not apply to searches by private parties unless those searches are conducted at the direc­tion of the government. Private parties who independently acquire evidence of a crime may turn it over to law enforcement.

For example, if an employee discovers contraband files on a computer that is being repaired in a shop, the employee’s subsequent release of information to law enforce­ment does not violate the Fourth Amendment. In such a case, law enforcement may examine anything that the employee observed.

Reasonable expectation of privacy
The Fourth Amendment applies when the searched party has an actual expectation of privacy in the place to be searched or thing to be seized, and then only if it is an expectation that society is prepared to recognize as reasonable.


 * [F]irst that a person have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as “reasonable."

The subjective part of the test focuses attention on the means the individual employs to protect his or her privacy, e.g., closing the door of a phone booth or closing curtains. Additionally, the assumption of risk that the individual appears to take is considered in determining the individual’s actual expectation of privacy. Under assumption of risk, an individual is presumed to assume the risk that another party to a conversation or activity may consent to a search. This assumption of risk prevails even if the consenting party is an informer or undercover agent.

The objective part of the test looks to what society regards as a reasonable expectation of privacy. Yet, it requires this without specifying an objective referent. Is “society” today’s opinion polls, longstanding norms and traditions, a reasonable person, or the knowledge that people have in common? The result of the objective part of the test is that the Court has implicitly constructed a continuum of circumstances under which society would regard an individual as having a reasonable expectation of privacy. The continuum ranges from public places (“open fields,” “in plain view,” “public highway”), in which there is no objective expectation of privacy except in unusual circumstances, to the inside of one’s home with the windows and curtains shut and the door bolted, in which there is an objective expectation of privacy. The objective expectation of privacy along the continuum (shopping centers, motels, offices, automobiles, and yards) depends on judicial interpretation. The Court has modified the objective element, referring to it as a ‘‘legitimate’ expectation of privacy."

Some courts treat a computer as a “closed container” for Fourth Amendment purposes. In some jurisdictions, looking at a computer’s subdirectories and files is akin to opening a closed container.

People, Not Places
The second important component of Katz v. United States is the holding that ‘‘the fourth amendment protects people, not places.” The question of what protection the fourth amendment offers people remains unanswered, and defining the scope of such protection still necessitates reference to places. Moreover, the distinction between “people” and “places” has raised the question of whether the fourth amendment still protects property interests, or whether it now protects only more personal interests. The issue of the protection afforded people as distinct from that afforded places has become more significant with the growth of third-party recordkeepers, e.g., banks. The thrust of the U.S. Supreme Court opinion in Katz seemed to represent an expansion, not a replacement, of the existing fourth amendment protections:


 * The amendment protects individual privacy against certain kinds of governmental intrusion, but its protections go further, and often have nothing to do with privacy at all.

It has been argued that, based on Katz, analysis of privacy interests should replace the more traditional property analysis when the Government uses nonphysical methods of search and where relevant privacy interests do not have physical characteristics. The property aspect is viewed as still important because it gives specificity and concreteness to fourth amendment analysis. Yet, in some rulings the U.S. Supreme Court has treated privacy as the only interest protected by the fourth amendment.

This implies a further narrowing of fourth amendment protection, both because property interests are not considered and because of the problems of defining privacy. In evaluating the appropriateness of the use of electronic surveillance technologies by Government officials, the courts have worked within the framework established by Katz. By analogy to traditional surveillance devices, the courts have attempted to determine whether or not individuals have a reasonable expectation of privacy. This becomes more difficult as surveillance devices become more technologically sophisticated because the analogy is often more remote and hence less convincing. The courts have generally continued to consider the place in which a surveillance device is located or the place that a device is monitoring. The courts generally have adopted the more expansive interpretation of Katz and have not abandoned higher levels of protection for certain places, e.g., homes and yards.

Yet, the Katz framework has not offered the courts sufficient policy guidance to deal with the range and uses of new surveillance technologies. "Reasonable expectation of privacy" is an inherently nebulous phrase and, despite decades of judicial application, predicting its meaning in a new context is difficult. Determining whether a place is sufficiently private to offer protection against official surveillance is more and more difficult as the public sphere of activities encroaches on what was once deemed private.

Privacy
The Fourth Amendment search and seizure provision protects a right of privacy by requiring warrants before government may invade one's internal space or by requiring that warrantless invasions be reasonable. However, "the Fourth Amendment cannot be translated into a general constitutional ‘right to privacy.’ That Amendment protects individual privacy against certain kinds of governmental intrusion, but its protections go further, and often have nothing to do with privacy at all."

Online communications
Computer users lack a legitimate expectation of privacy in information regarding the to/from addresses for e-mails, the IP addresses of websites visited, the total traffic volume of the user, and other addressing and routing information conveyed for the purpose of transmitting Internet communications to or from a user. E-mail addresses and IP addresses provide addressing and routing information to an Internet service provider (ISP) in the same manner as a telephone number provides switching information to a telephone company. Just as a telephone user has no objectively reasonable expectation of privacy in telephone numbers voluntarily turned over to the phone company to enable switching of a phone call, an Internet user has no such expectation of privacy in routing information submitted to an ISP in order to deliver an Internet communication. That routing information also is akin to the addressing information written on the outside of a first-class letter, which also is not constitutionally protected.

With respect to information regarding the total volume of data received and transmitted by an Internet user, that information is no different from the information produced by a pen register regarding the number of incoming and outgoing calls at a particular phone number; and the Supreme Court has long held that an individual has no legitimate expectation of privacy in such information, which already has been exposed to a telecommunications carrier for the purpose of routing a communication. With respect to the content of an Internet communication (such as an e-mail), a computer user generally has a legitimate expectation of privacy in that content while it is in transmission over the Internet. To date, the federal courts appear to agree that the sender of an e-mail, like the sender of a letter via first-class mail, has an objectively reasonable expectation of privacy in the content of a message while it is in transmission.

Federal courts agree that, again like the sender of a first-class letter, an individual has a “diminished” expectation of privacy in the content of an e-mail that “ha[s] already arrived at the recipient.”