Jonathan and Diana Toebbe pleaded guilty for a second time on Tuesday to federal charges that they tried to sell secrets about U.S.

At the time of his plea, Toebbe conceded he sent a package to a foreign government, listing a return address in Pittsburgh that contained a sample of restricted data and instructions for establishing relationship to buy additional restricted data.

A few weeks later, Jonathan and Diana Toebbe traveled to a location in West Virginia, prosecutors said.

There, with Diana Toebbe acting as a lookout, Jonathan Toebbe placed an SD card concealed within half a peanut butter sandwich at a pre-arranged "dead drop" location, they said.

Diana Toebbe, 46, pleaded guilty to a single count of conspiracy to communicate restricted data, conceding she "knowingly and voluntarily" joined a conspiracy with her husband, a former nuclear engineer for the U.S.

Jonathan Toebbe, 43, also pleaded guilty to a single count of conspiring to communicate restricted data pursuant to an agreement that calls for a sentence of up to 17 years in prison.