Former Los Alamos Lab Workers Sentenced

Nuclear Scientist and Wife Passed Classified Documents


The reasons why he did it varied—he carried a grudge against his employer, he was frustrated with the U.S. government, he needed money, and he desired power and respect. But motivations aside, Pedro Leonardo Mascheroni, a scientist formerly employed at the Los Alamos National Laboratory in New Mexico, broke the law when he sold some of our nation’s nuclear secrets to an individual he thought was a foreign government official. He also involved his wife—a Los Alamos employee at the time—in his illegal activities.

Both were charged and eventually pled guilty in connection with the plot. Last month, Pedro Mascheroni was sentenced to a federal prison term, while his wife—Marjorie Roxby Mascheroni—was sentenced last summer.

Pedro Mascheroni, a naturalized American citizen born in Argentina, had a Ph.D. in physics when he began working at Los Alamos in 1979. Los Alamos National Laboratory is one of several nuclear weapons labs in the country. During the majority of his time there, Mascheroni held a Department of Energy security clearance that allowed him access to certain classified information, including “restricted data,” a specific type of classified data dealing with nuclear weapons-related material. Marjorie Mascheroni, who worked as a technical writer and editor, had similar access.

In 1988, Pedro Mascheroni left Los Alamos as a result of a downsizing initiative, but Marjorie continued her employment with the lab.

Move ahead to the fall of 2007: Mascheroni, by his own admission, contacted a Venezuelan official in the U.S. and offered his expertise and assistance to build a nuclear weapons program for that nation. That contact ultimately provided the FBI an opportunity to engage the scientist, in early 2008, through an undercover agent posing as a Venezuelan government official.

A note here: The indictment in this case did not allege that the government of Venezuela or anyone acting on its behalf sought or was passed any classified information, nor did it charge any Venezuelan government officials or anyone acting on their behalf with any wrongdoing.

In March 2008, Mascheroni had a series of discussions with our “Venezuelan government official” about his program to develop nuclear weapons for Venezuela. Among other things, he told the official/undercover agent that he could help Venezuela develop a nuclear bomb within 10 years and that, under this program, Venezuela could use a secret, underground nuclear reactor to produce and enrich plutonium and an open, above-ground reactor to produce nuclear energy. Mascheroni also asked our undercover agent about obtaining Venezuelan citizenship and explained how much he expected to be paid for his work.

Over the next year-and-a-half—through e-mail, dead drops, and face-to-face meetings—Mascheroni passed to our agent documents he had written using classified and sometimes restricted data. During that time, he also received his first cash payment of $20,000. Marjorie Mascheroni conspired with her husband by editing his written documents and occasionally accompanying him on dead drops and face-to-face meetings.

By October 2009, we had obtained enough evidence to search the Mascheronis’ home, where we found several boxes of classified documents, sketches, plans, and notes—along with classified information on his computer—all from Los Alamos. Despite the fact that Pedro Mascheroni had left Los Alamos in 1988, the information, particularly the restricted data on nuclear weapons, was still relevant, still classified, and still harmful to U.S. national security if it fell into the wrong hands.

Special thanks to the Department of Energy and the Los Alamos National Laboratory for their assistance in this case, which serves as an example of the FBI’s commitment to its mandate to expose, prevent, and investigate intelligence activities on U.S. soil.