Norfolk, Va. ? A Navy lawyer was found guilty Thursday of communicating secret information about Guantanamo Bay detainees that could be used to injure the United States and three other charges of leaking information to an unauthorized person.

Lt. Cmdr. Matthew Diaz was acquitted of printing out national defense information with the intent or reason to believe it would be used against the United States.

Diaz, 41, of Topeka, Kan., did not testify in the court martial hearing. He could face up to 14 years in prison at sentencing. That hearing will begin today.

The military jury of seven Navy officers began deliberations Thursday at Norfolk Naval Station after hearing 3 1/2 days of testimony. Much of the testimony brought before the jury and a Navy judge centered on what constitutes classified information.

Prosecutors contended Diaz mailed a human rights lawyer a printout of the names of 550 Guantanamo Bay detainees tucked into an unsigned Valentine’s Day card. They said Diaz’s actions endangered the lives of the detainees and of American troops.

Defense attorneys said the information was not labeled classified and that Diaz had no reason to think the document could be used to injure the United States.

Patrick McLain, Diaz’s civilian lawyer, acknowledged that his client sent a card to Barbara Olshansky containing names and other identifying information about detainees.

“We’ll be frank till the cows come up that this was imprudent, dumb, sneaky, if you want, in the way he sent it off,” McLain said in his closing, but the information didn’t compromise national security and Diaz intended no harm to the United States.

Cmdr. Rex Guinn, the lead prosecutor, said that because Diaz mailed the card and information on his last day at Guantanamo, it proved the act was deliberate and calculated.

“As a Naval officer, he had a duty to protect classified information,” Guinn said. “He had a duty to protect his client’s information. He failed to do so. It wasn’t by accident. It was deliberate, on purpose. It brings dishonor and disgrace on him.”

According to prosecutors, Diaz went to his office in January 2005 and used his classified computer to log onto a classified military network and access a Web-based database with information about the detainees. He printed information that included the names of 550 detainees, their nationalities, the interrogators assigned to them and intelligence sources and methods, cut the document into 39 sheets that he placed inside a card with a big heart and a Chihuahua on its front and mailed it to Olshansky.

Olshansky then worked for the Center for Constitutional Rights, a nonprofit legal group that was suing the federal government to obtain the names of detainees because the U.S. Supreme Court had ruled that they had the right to challenge their detention.

She turned the document over to federal authorities, and they traced it to Diaz.