Opinion | Arrested: Can the Police Search My Phone?

The Supreme Court's Stance?

In recent years, news reports, media, and social platforms may have highlighted certain social cases where law enforcement solved crimes precisely because they inspected a criminal suspect's or defendant's phone. In some instances, law enforcement obtained the defendant's phone through a court-issued search warrant and subsequently inspected it to gather evidence. In other situations, however, it appears that law enforcement conducted a lawful arrest, searched the defendant's person, and seized the phone for inspection.

Smartphones used in modern life often store a vast amount of critical personal privacy. Can we truly allow the police to inspect a criminal suspect's phone through a search without a warrant (albeit under a lawful arrest)?

Regarding this issue, in April of last year (2025), our Supreme Court rendered a highly significant judgment—Taiwan Supreme Court 114 Tai-Shang-Tzu No. 687 Criminal Judgment.

Historically in our judicial practice, controversy has long surrounded whether the contents of a defendant's phone may be examined during various forms of "warrantless searches." (As a rule, searches must be executed pursuant to a "search warrant" issued by a court, though there are exceptions where law enforcement may conduct a lawful "warrantless search." For instance, "search incident to arrest," as discussed later in this article, is a type of lawful warrantless search.) Taking a "search incident to arrest" executed during the apprehension of a flagrant offender as an example, our Code of Criminal Procedure provides regarding searches incident to arrest:

Article 130
When arresting a defendant or criminal suspect, or executing an apprehension or detention, prosecutors, prosecutors' investigators, judicial police officers, or judicial police may, even without a search warrant, directly search their person, articles carried on their person, vehicles used by them, and places immediately accessible to them.

Judging from the statutory text, if a criminal suspect is carrying a phone, it would also meet the criteria of "articles carried on their person" and should fall within the scope of a "search incident to arrest." However, does lawfully "taking" the phone mean one is automatically entitled to "look" at it?

On this issue, academic opinions diverge sharply. Some argue that "since the arrest is lawful, and the law stipulates that articles carried on the person may be searched, seizing and searching the phone to inspect it constitutes a lawful procedure." Others maintain that "the purpose of a search incident to arrest is to protect the safety of law enforcement personnel (verifying the presence of weapons) and to prevent the immediate destruction of evidence; therefore, inspecting the contents of a phone should bear no relevance to these purposes."

This controversy was addressed in the reasoning of the Supreme Court's 114 Tai-Shang 687 judgment, which established two fundamental stances on the issue:

1. In cases of "consent search," the mere fact that a criminal suspect consents to hand over their phone does not imply consent to the inspection of its contents.
   
2. In cases of "search incident to arrest," because the purpose of a search incident to arrest is to protect law enforcement safety and prevent the destruction of evidence, the contents of a phone likewise cannot be inspected unless there is a likelihood of evidence destruction.
   

Regarding the relationship between mobile phones and the right to privacy, the judgment elaborates on the significance of private information inside phones to modern individuals, stating: "Mobile phones are closely intertwined with daily life; the electromagnetic record contents within them deeply and broadly encompass the informational privacy spheres of both criminal suspects and third parties. Much of this content is unrelated to the prosecution of crimes or the evaluation of culpability, and some even constitutes the core private domain of personality rights that is absolutely immune to state infringement."

The aforementioned perspectives in the 114 Tai-Shang 687 judgment can be said to provide certain inspiration for our nation's privacy protection reasoning. However, concerning the question of "why phones are so crucial to privacy," the U.S. Supreme Court in the 2014 case of *David Leon Riley v. California, United States v. Brima Wurie* (hereinafter the "Riley case") offered much more profound elaborations on "the privacy significance of mobile phones in modern human life," along with some "fascinating analogies" favored by the authors, offering readers greater imaginative space in viewing the developmental trajectory of our country's jurisprudence on this issue.

Is a Phone a "Container"?

The factual backgrounds of both cases in *Riley* arose from incidental "searches incident to arrest" conducted during police law enforcement.

In the first case, the defendant, Riley, was pulled over by police for an expired license plate. Because officers found two handguns under the hood, they arrested Riley on the spot for "unlawful weapons possession." Upon searching Riley's phone, police uncovered evidence of his participation in gang crimes (including shooting incidents, attempted murder, etc.).

In the second case, police discovered during routine patrol that the defendant, Brima Wurie, was selling drugs and arrested him on the spot. Upon checking Wurie's phone, officers traced communication contents to locate his residence, obtained a search warrant from the court, and subsequently seized drugs, weapons, and cash from his home.

At the time, American legal practice precedent held that during a search incident to arrest, officers could lawfully search "containers" on a suspect's person (for example, opening a cigarette pack to search for drugs hidden inside). Consequently, whether a mobile phone qualifies as a "container" became the most critical contentious issue in the case.

The Modern Significance of Mobile Phones to Human Life and Privacy

In this U.S. Supreme Court ruling, the ubiquity of mobile phones in modern life was first described in the following manner:

They are now such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude they were an important feature of human anatomy.

As for whether a mobile phone constitutes a "container," the U.S. federal government's prosecutors argued that searching the data stored on a phone is no different from searching physical items like a cigarette pack—both involve searching for evidence and gathering privacy-related information, and they should be identical in terms of privacy infringement. In response, the Supreme Court held:

The United States asserts that a search of all data stored on a cell phone is “materially indistinguishable” from searches of these sorts of physical items. That is like saying a ride on horseback is materially indistinguishable from a flight to the moon. Both are ways of getting from point A to point B, but little else justifies lumping them together.

How do mobile phones actually differ from ordinary items (containers)? The judgment also offered the following description of what would happen "if the information on a mobile phone were to be physicalized":

Most people cannot lug around every piece of mail they have received for the past several months, every picture they have taken, or every book or article they have read—nor would they have any reason to attempt to do so.

Furthermore, the sheer volume of information disclosed by a mobile phone is incomparable to that of ordinary containers (such as a wallet):

[A] cell phone’s capacity allows even just one type of information to convey far more than previously possible. The sum of an individual’s private life can be reconstructed through a thousand photographs labeled with dates, locations, and descriptions; the same cannot be said of a photograph or two of loved ones tucked into a wallet.

Beyond the collection of information such as photographs, the Supreme Court also noted that even the many software applications we use daily can yield extensive private information, explaining that:

Mobile application software on a cell phone, or “apps,” offer a range of tools for managing detailed information about all aspects of a person’s life. There are apps for Democratic Party news and Republican Party news; apps for alcohol, drug, and gambling addictions; apps for sharing prayer requests; apps for tracking pregnancy symptoms; apps for planning your budget; apps for every conceivable hobby or pastime; apps for improving your romantic life. There are popular apps for buying or selling just about anything, and the records of such transactions may be accessible on the phone indefinitely. There are over a million apps available in each of the two major app stores; the phrase “there’s an app for that” is now part of the popular lexicon. The average smart phone user has installed 33 apps, which together can form a revealing montage of the user’s life.

Crucially, the judgment went even further to clarify that because cloud data is not actually stored on the phone itself, using a phone to access and view cloud-based data constitutes an even more boundless invasion of privacy (making the "container" analogy completely untenable):

To further complicate the scope of the privacy interests at stake, the data a user views on many modern cell phones may not in fact be stored on the device itself. Treating a cell phone as a container whose contents may be searched incident to an arrest is a bit strained as an initial matter (describing a “container” as “any object capable of holding another object”). But the analogy crumbles entirely when a cell phone is used to access data located elsewhere, at the tap of a screen.

How Much Are We Willing to Pay to Protect Privacy?

In summary, the U.S. Supreme Court held that because mobile phones cannot be readily analogized to containers in a search incident to arrest, and because the purpose of a search incident to arrest bears no connection to the information inside a phone, it ruled that arresting a criminal suspect does not grant the right to search their phone (not even during the lawful arrest of a flagrant offender). If there is a genuine necessity to inspect a phone, the appropriate course of action is to seize the suspect's phone and obtain a search warrant from a court (meaning obtaining prior judicial authorization) before conducting the inspection.

In conclusion, the U.S. Supreme Court adopted a candid attitude, telling us that choosing to protect privacy does not come without a price:

We cannot deny that our decision today will have an impact on the ability of law enforcement to combat crime. Cell phones have become important tools in facilitating coordination and communication among members of criminal enterprises, and can provide valuable incriminating information about dangerous criminals. Privacy comes at a cost.

Remarkably, this conclusion was unanimously endorsed at the time (2014) by all nine justices of the Supreme Court (with only one justice writing a concurring opinion), leaving the authors sincerely admiring the dedication and steadfast commitment to privacy protection demonstrated in this judgment.

The authors also hope that the 114 Tai-Shang 687 judgment, rendered just last year, will serve as another starting point for legal practice to begin reflecting anew on "how to protect privacy" in the future.

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*This article was published in "Up Media / Arrested: Can the Police Search My Phone?"