MARTINSBURG, W.Va. (WDVM) — A federal judge in Martinsburg, West Virginia ordered a Maryland couple held in confinement on charges they tried to sell U.S. nuclear submarine secrets.

A black unmarked van driven by U.S. Marshals whisked Jonathan and Diana Toebbe away from the federal courthouse in Martinsburg after their preliminary hearing on espionage charges.

Jonathan is a U.S. Navy nuclear engineer, while his wife Diana is a public school teacher. They allegedly sold thousands of pages of classified secrets about nuclear submarine propulsion systems to a contact that happened to be working for the FBI.

Paul Taylor is a Martinsburg lawyer who has argued in federal court.

“It’s an opportunity for the government to demonstrate they have a sufficient basis to proceed forward with prosecution of the criminal charges,” Taylor explains.

The preliminary hearing was held in West Virginia because that’s where the couple was arrested making their “dead drop.” Their delivery of the secret files was reduced to a memory card hidden in a peanut butter sandwich.

Both defendants were required to submit a financial statement should they request a court-appointed attorney.

“You have to meet or be below a certain threshold to qualify for court-appointed counsel, and that’s typically what the financial affidavit is used for,” said Taylor.

Their Annapolis, Maryland neighbors say the Toebbes were a very private couple. Diana’s students were shocked, calling her passionate about teaching.

A detention hearing is set for Friday in the same courtroom. That isn’t the only hearing for the couple. They will be in court again next week for a “probable cause” hearing.