A Federal Protection Service vehicle is seen parked outside the federal courthouse where former U.S. Navy engineer Jonathan Toebbe and his wife Diana face their first court hearing on charges that they attempted to sell secrets about nuclear submarines to
A Federal Protection Service vehicle is seen parked outside the federal courthouse where former U.S. Navy engineer Jonathan Toebbe and his wife Diana face their first court hearing on charges that they attempted to sell secrets about nuclear submarines to a foreign power in exchange for cryptocurrency, in Martinsburg, West Virginia, U. Reuters / KEVIN FOGARTY

A former U.S. Navy engineer charged with attempting to sell secrets about nuclear submarines to a foreign power pleaded guilty on Monday as part of a deal with prosecutors.

A U.S. Justice Department lawyer unveiled the agreement with nuclear engineer Jonathan Toebbe during a court hearing in West Virginia federal court.

Toebbe, 42, admitted to conspiring with his wife to disclose restricted data, a violation of the Atomic Energy Act that carries a maximum sentence of life in prison.

Toebbe's 45-year-old wife, Diana, who was charged with helping her husband, is still facing criminal charges. She has pleaded not guilty.

Toebbe's plea agreement calls for him to face a likely sentence of between 12 years to 17 years in prison.

The plea deal "indicates that the government likely had a very strong case and saw this conduct as posing a very serious risk to national security," said Brandon Van Grack, a national security lawyer at Morrison & Foerster not involved in the case.

Prosecutors alleged in an October indictment that the Toebbes tried to sell government secrets about nuclear submarine propulsion to an unidentified foreign country.

Toebbe, who had a top-secret security clearance, communicated with an undercover FBI agent posing as a foreign official over the course of several months, the Justice Department said.

At one point, Toebbe hid a digital memory card containing documents about submarine nuclear reactors in half a peanut butter sandwich at a "dead drop" location in West Virginia while his wife acted as lookout, the Justice Department said.

The memory card contained "militarily sensitive design elements, operating parameters and performance characteristics of Virginia-class submarine reactors," according to the Justice Department.

An FBI agent testified during a court hearing in October that Toebbe asked for $5 million worth of cryptocurrency in exchange for the secret submarine information. A payment made by the FBI to Toebbe worth about $100,000 has not been located, the agent testified.