Jack Douglas Teixeira of North Dighton, Massachusetts, who was arrested by a team of heavily armed FBI agents at his home on Thursday, appeared in federal court wearing a brown khaki jumpsuit.
It is believed to be the most serious security breach since more than 700,000 documents, videos and diplomatic cables appeared on the WikiLeaks website in 2010. In the WikiLeaks case, the leaker - U.S. Army Private First Class Chelsea Manning - was sentenced to 35 years in prison. Democratic President Barack Obama later commuted her sentence.
He was also charged with another offense which makes it a crime for an employee of the United States to knowingly remove classified records to an unauthorized location. Teixeira only spoke twice during the brief proceeding, answering"yes" when asked if he understood his right to remain silent.