If you get arrested, police can likely access your phone or tablet

An inquiry from a reader:

On June 25, the U.S. Supreme Court unanimously ruled that police need warrants to search the cellphones of people arrested. The ruling almost certainly applies to searches of tablet and laptop computers, and its reasoning may apply to information held by third parties like phone companies.

What is the law here in Japan? May police search a person’s cellphone, tablet or laptop computer without a warrant, and would any privacy or civil-liberty protections provided by law apply to both Japanese and non-Japanese?

Unlike in the U.S., the law in Japan is silent on this particular issue. However, on a practical level, most Japanese lawyers are in no doubt that investigating authorities — essentially, police and prosecutors — have the right, absent a warrant, to search the cellphones of arrested suspects.

Before going any further, it’s important to understand that intangibles such as information are not covered by rules of seizure by investigating authorities under Japanese law. What this means is there is no such thing as a warrant issued specifically for the seizure of the information held on cellphones, tablets, laptops, desktop computers and so on. However, this doesn’t mean that investigating authorities have carte blanche to search such seized devices or gain all the information in them in every circumstance. Put simply, police and prosecutors can search a device only when there is the probability that information relating to a particular case might be stored there.

For example, if someone has been arrested on suspicion of selling illegal drugs, the police could seize and search the suspect’s cellphone because information pertinent to the case, such as the phone numbers of clients, could be stored on it. On the other hand, if a suspect has been arrested for shoplifting, apparently without accomplices, the investigating authority couldn’t seize or search their cellphone, unless that authority had a reasonable suspicion that the phone was somehow used in the act of committing the crime.

Now, do police and prosecutors have the authority to unlock a phone using the suspect’s personal passcode without a warrant? The answer is yes: Since criminal procedure law says that investigating authorities can take such measures as unlocking or unsealing seized articles, it follows that seized phones and other devices could also be unlocked electronically based on this clause.

Jun Kajita is an attorney with the Foreigners and International Service Section at Tokyo Public Law Office, which handles a wide range of cases involving foreigners in the Tokyo area (; 03-6809-6200). FISS lawyers address readers’ queries once a month. Questions:

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