The Navy nuclear engineer and his wife accused of selling U.S. Navy submarine secrets to a foreign power could face a potential maximum penalty of life in prison. 

Jonathan and Diana Toebbe, of Annapolis, were arrested Saturday in Jefferson County, West Virginia, on espionage-related charges. Federal prosecutors say they should remain in custody pending their trials as they face a potential maximum penalty of life in prison and are at "serious risk" of fleeing. 

The couple is being charged with violating the Atomic Energy Act, which restricts the disclosure of information related to atomic weapons or nuclear materials. 

NAVY NUCLEAR ENGINEER'S WIFE ARRESTED FOR SELLING SECRETS APPEARS TO SUPPORT BLM, 'RESISTANCE' MOVEMENTS

"Unfortunately there always will be people willing to compromise our nation’s security for personal gain. It’s treasonous, it’s rare, but such individuals are traitors and should be held accountable to the fullest extent of the law," former acting United States Secretary of the Navy Thomas Modly told Fox News.

"Our nuclear submarine force provides a significant military capability for the United States. It is a capability our adversaries both covet and fear. Information related to it must be protected – and for the most part, it is," he added. 

The residence of Jonathan and Diana Toebbe is shown on Sunday, Oct. 10, 2021 in Annapolis, Md., a day after neighbors say the house was searched by FBI agents. Jonathan Toebbe, a Navy nuclear engineer, has been charged with trying to pass information about the design of American nuclear-powered submarines to someone he thought was a representative of a foreign government but who turned out to be an undercover FBI agent. His wife also was arrested. (AP Photo/Brian Witte)

The residence of Jonathan and Diana Toebbe is shown on Sunday, Oct. 10, 2021 in Annapolis, Md., a day after neighbors say the house was searched by FBI agents. Jonathan Toebbe, a Navy nuclear engineer, has been charged with trying to pass information about the design of American nuclear-powered submarines to someone he thought was a representative of a foreign government but who turned out to be an undercover FBI agent. His wife also was arrested. (AP Photo/Brian Witte) ((AP Photo/Brian Witte))

An unsealed criminal complaint alleges that Jonathan Toebbe contacted an unidentified foreign nation in April 2020 to sell U.S. Navy submarine secrets. The FBI, however, obtained Toebbe’s documents and began communicating with him undercover in December. 

The Toebbes hid data cards in items such as a peanut butter sandwich, a Band-Aid wrapper, and a chewing gum package, so the information could be picked up by who they believed was a foreign spy operative, authorities say. 

Diana Toebbe is accused of "acting as a lookout" as her husband dropped off the material. 

"Although most spy cases don’t involve peanut butter and Band-Aids, the facts alleged follow a familiar pattern: Insider within the U.S. government approaches a foreign power to sell U.S. secrets for money, is compromised despite their best efforts at tradecraft, and — to their surprise — is subsequently arrested," David Laufman, a former senior Justice Department official, told the Washington Post

NAVY NUCLEAR ENGINEER CHARGED WITH TRYING TO PASS SECRETS

Prosecutors allege that Jonathan Toebbe also told his contact person that he might need to leave the country on short notice. 

"Should that ever become necessary, I will be forever grateful for your help extracting me and my family," the document quoted him as writing. "I surmise the first step would be unannounced travel to a safe third country with plans to meet your colleagues. We have passports and cash set aside for this purpose."

They are scheduled for an initial appearance Tuesday morning. Prosecutors are requesting a detention hearing later in the week, the Baltimore Sun reported.

Fox News reported on Monday – after reviewing what appears to be the Toebbes’ social media accounts – that Diana Toebbe had multiple Facebook and Twitter posts in support of Black Lives Matter, anti-Trump posts, and followed "resistance" accounts on Twitter. 

Diana Toebbe is a teacher at the private Key School in Annapolis, and has since been indefinitely suspended from her job after the arrests.

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One neighbor of the Annapolis couple, Jennifer McCormick, described the Toebbes as quiet, saying they moved to the neighborhood in 2014.

"They didn't talk to anybody, even on the block," McCormick told Fox News. "We've lived here over 20 years. They moved here in 2014 and been up and down this block so many times. And we would see them and never even say, hi, don't even like catch your eye."