Ex-Navy officer Matthew Diaz kept it real. Now he may go to jail.

Raised in San Bernardino, California, Lieutenant Commander Diaz had a rough childhood. His parents divorced when he was six and he attended nine different schools before starting junior high. By the time he was 17, Diaz had dropped out of high school and was living in a motel after his father, a nurse, was convicted of murdering his elderly patients – a conviction Diaz helped to fight by investigating the court transcripts.

Determined to turn his life around, Diaz enlisted in the Army, earning an associate's degree in law enforcement and a bachelor's in criminology. He eventually left the Army to pursue a law degree in the Navy, partly inspired by Latino actor Jimmy Smits, who appeared in the popular '80s TV drama L.A. Law.

Recognized for his outstanding service record, Diaz joined the Navy Judge Advocate General's Corps (the Navy's lawyers) and was assigned to the Guantánamo Bay detention camp in 2004 to investigate allegations of prisoner abuse. The infamous military prison, nicknamed "Gitmo," houses suspected terrorists, all designated enemy combatants – a designation that strips them of many legal rights. Just before Diaz was assigned to Guantánamo, the U.S. Supreme Court ruled that the detainees at the prison had the right of habeas corpus – the ability to challenge his or her detention.

In early 2005, as Diaz was nearing the end of his six-month tour of duty, he came to believe Guantánamo detainees were still being denied their rights: they were being held in secret, their complaints were suppressed, and the military was failing to document their conditions.

Shocked and disgusted, Diaz copied the names of all 551 prisoners being held in Guantánamo; the names had not been marked secret though they should have been. On his last day, Diaz stuffed this list into a Valentine's Day card and sent it to Barbara Olshansky, a lawyer at the liberal Center for Constitutional Rights. Diaz wanted to make the names public so the detainees could dispute their detention.

Olshansky, who had previously requested the names of prisoners from the federal government without success, thought the valentine was a hoax. She contacted a federal agent who traced the leak back to Diaz. Within weeks, he was court-martialed for "improper disclosure of classified information" and was later sentenced to six months in prison.

For exposing government secrets, the 42-year-old Diaz, who served in the military for 19 years, has been called both a traitor and a hero. Diaz is currently appealing his sentence and says he may have gone about things the wrong way but is certain he had to do something: “I knew that if I didn’t do anything, nobody else was going to.” He is now reviewing the transcripts of his hearing — as he once reviewed those of his father.