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Police blotter: Cops OK to copy cell phone content

Truck driver arrested on drug charges says state troopers needed a warrant before copying contents of his cell phones.

Declan McCullagh Former Senior Writer
Declan McCullagh is the chief political correspondent for CNET. You can e-mail him or follow him on Twitter as declanm. Declan previously was a reporter for Time and the Washington bureau chief for Wired and wrote the Taking Liberties section and Other People's Money column for CBS News' Web site.
Declan McCullagh
4 min read

Police blotter is normally a weekly News.com report on the intersection of technology and the law. This is an extra edition.

What: Kansas state trooper stops truck driver, arrests him for alleged drug possession, and downloads contents of his cell phones.

When: U.S. District Judge Sam Crow in Kansas rules on April 12.

Outcome: Judge says copying of cell phones' contents was permissible.

What happened, according to court documents:
In December 2006, Kansas Highway Patrol Trooper Clint Epperly was staffing a drug checkpoint at a truck weighing station in Wabaunsee County. Rafael Mercado-Nava was driving a tractor-trailer and stopped at the checkpoint around midnight.

When Mercado-Nava got out of his truck at the scale house, the trooper was suspicious, claiming that the driver was sweating, overly friendly, and the truck was registered in California (which Epperly believed to be a source of illegal drugs).

Mercado-Nava's paperwork was in order. But during an inspection of the cab of the tractor-trailer, Epperly discovered a hidden compartment that allegedly contained 18 kilograms of cocaine under the floor.

The typical sequence of events ensued: Mercado-Nava was arrested, and a drug dog allegedly confirmed that the substance was cocaine.

What makes this case relevant to Police blotter is that Epperly and one of his colleagues copied the complete contents of the suspect's two cell phones. Mercado-Nava's attorney eventually filed a motion to suppress the digital contents from being used against his client in court, claiming they were seized illegally without a warrant.

The U.S. Constitution's Fourth Amendment, of course, prohibits "unreasonable" searches and seizures. In general, a search without a warrant is viewed as unreasonable.

But searches when a person is arrested are an exception to that general rule. In this case, the judge upheld the search as constitutional, saying that: "An officer's need to preserve evidence is an important law enforcement component of the rationale for permitting a search of a suspect incident to a valid arrest."

This raises issues--especially when hard drives that can store intimate life details are growing in capacity and shrinking in size. If someone is arrested for speeding and has a laptop next to him on the seat, Crow's reasoning could mean that a law enforcement officer is permitted to seize the laptop and copy its entire contents. Homeland Security already has the authority to do that at border crossings, according to the 9th Circuit Court of Appeals.

One lesson that law-abiding citizens, who nonetheless want to protect their privacy, can take from this incident is to use encryption and a strong passphrase whenever possible. Here are some technical tips. Apple's OS X operating system includes a FileVault feature, and PGP offers whole disk encryption for Windows. In addition, there are some legal arguments that people accused of a crime cannot be compelled to divulge their passphrase.

Excerpt from the district court's opinion:
The sole evidence regarding this issue is that two cellular telephones were seized from defendant's person, without a warrant and without consent, contemporaneously with defendant's arrest, and their memories were downloaded at that time, before defendant was processed or booked. No evidence suggests that the contents of the phones were protected by a password or that the information retrieved by the troopers consisted of anything other than stored numbers of outgoing and incoming calls.

Traditionally, there has been no reasonable expectation of privacy in the numbers dialed on one's phone, since by voluntarily conveying numerical information to the telephone company and exposing that information to its equipment in the ordinary course of business, one loses any reasonable expectation of privacy in the existence and identity of such calls.

The same rationale has recently been applied to cell phones. Other courts have found that the expectation of privacy in similar cases is analogous to the expectation of privacy one has in the contents of a closed container, or in a personal telephone book containing directory information.

A warrantless search violates the Fourth Amendment unless it falls within one of the enumerated exceptions to the warrant requirement. These exceptions include, among others, warrantless searches incident to a lawful arrest.

Traditional search warrant exceptions apply to the search of cell phones. Where the accessing of memory is a valid search incident to arrest, the court need not decide whether exigent circumstances also justify the officer's retrieval of the numbers from it.

Police officers are not constrained to search only for weapons or instruments of escape on the arrestee's person; they may also, without any additional justification, look for evidence of the arrestee's crime on his person in order to preserve it for use at trial. The permissible scope of a search incident to a lawful arrest extends to containers found on the arrestee's person.

The need to preserve evidence is underscored where evidence may be lost due to the dynamic nature of the information stored on and deleted from cell phones or pagers. An officer's need to preserve evidence is an important law enforcement component of the rationale for permitting a search of a suspect incident to a valid arrest.

Because of the finite nature of a pager's electronic memory, incoming pages may destroy currently stored telephone numbers in a pager's memory. The contents of some pagers also can be destroyed merely by turning off the power or touching a button. Thus, it is imperative that law enforcement officers have the authority to immediately "search" or retrieve, incident to a valid arrest, information from a pager in order to prevent its destruction as evidence.

The court finds that under the circumstances of this case, the government has met its burden to show that the troopers' search of the cell phones by accessing stored numbers was justified as a search incident to arrest.