A former National Guard officer and his ex-wife pleaded innocent to charges they attempted to sell illegally obtained national security secrets that the FBI said are worth millions of dollars.

Rafael Davila, 51, and Deborah Davila, 40, entered their pleas at a detention hearing Thursday.

Both have been held without bail since their arrest Tuesday, and U.S. Magistrate Cynthia Imbrogno ordered Friday that they be held without bail until trial. She said the government had proved there was no way to guarantee the pair would show for trial.

If convicted, the Davilas each face up to 10 years in prison and $250,000 in fines.

The stolen documents related to U.S. chemical, nuclear and biological capabilities still have not been recovered, said FBI agent Lee McEuen.

"They are worth, on the black market, millions of dollars, and would be of huge interest to militias and terrorist organizations," he testified. "Based on that, I believe they are a huge danger to the United States."

Prosecutors said that because many of the more than 300 documents are secret or top secret, they could not specify what they contained. Assistant U.S. Attorney Earl Hicks said there was no evidence the documents had reached foreign governments. He also said the suspects have not divulged where the documents are.

Defense lawyers argued that the Davilas had cooperated with the government, and were not a danger to the community or a flight risk.

Deborah Davila, a special education teacher, "has not tried to secret herself," said her attorney, Chris Phelps. Rafael Davila's lawyer, Roger Preven, said his client, who was an intelligence officer when he left the Washington Army National Guard service in 1999, had cooperated with authorities.

Prosecutors allege in a federal indictment that from January through mid-August of 1999, the Davilas had unauthorized possession of sensitive documents. Deborah Davila was also charged with trying to deliver the documents to an unidentified person who was not authorized to receive them.

The indictment said Deborah Davila lied to federal agents when she said she did not recognize the name of Kirk Lyons, an attorney who has represented leaders of the Ku Klux Klan and the anti-tax Posse Comitatus at trials, and had never met him.

The indictment does not say what connection, if any, Lyons has with the case.

Lyons, of Black Mountain, N.C., said Wednesday he did not know Rafael Davila, barely knew Deborah Davila and had no connection to any espionage.