It sounds like something James Bond would use: a gadget that self-destructs if it falls into the wrong hands. But it’s actually an open-source operating system that can be downloaded onto Android phones.

Federal prosecutors in Atlanta are bringing an obstruction charge against a U.S. citizen who gave customs officers what is known as a duress passcode, which activated software that erased the contents of his phone.

The authorities stopped Samuel Tunick, an Atlanta resident, for interrogation at Hartsfield-Jackson Atlanta International Airport as he returned to the United States on Jan. 24 last year, according to a November grand jury indictment. The authorities seized his phone before allowing him to enter the country. A hearing on the case was held last week in federal court in Atlanta.

The prosecution is one of the earliest known instances of federal authorities charging a person with destroying evidence with a program designed to wipe a device when a specific code is entered.

Mr. Tunick’s lawyers argued during the hearing last week that the seizure was unlawful, and that he was targeted because of his political activism against Atlanta’s plan to build a police and fire training center within a 1,000-acre stretch of urban woodland. Opponents argue that the center, known as Cop City, would militarize officers and destroy precious green space.

The Statute Behind the Charge

The federal statute underlying the charge makes it a felony to destroy evidence or transfer assets to keep the government from seizing them, or to tip someone off about an upcoming search or wiretap. It carries a penalty of up to five years in federal prison, a fine, or both.