(CNN) Following a year-long operation by undercover FBI agents, a Maryland couple has been arrested and charged with attempting to sell US nuclear secrets to another country in exchange for cryptocurrency.

US Navy nuclear engineer Jonathan Toebbe, who held a top-secret security clearance, and his wife Diana were arrested Saturday in West Virginia by the FBI and Naval Criminal Investigative Service after the couple allegedly sold information concerning the design of nuclear-powered US warships "to a person they believed was a representative of a foreign power but was actually an undercover FBI agent," according to a Department of Justice statement.

The Washington Post first reported on the alleged espionage plot.

The Justice Department said Toebbe had access to information on naval nuclear propulsion and sensitive military design elements including "operating parameters and performance characteristics of the reactors for nuclear powered warships."