The contractor reportedly worked for the consulting firm, Booz Allen (BAH). That is the same firm where the most famous NSA leaker, Edward Snowden, was employed when he made off with documents that revealed controversial surveillance programs used by the U.S. government to collect information from phone and Internet companies.

The Justice Department says Martin was arrested on August 27 and that it filed a criminal complaint the next day, which it has now unsealed. In a release describing the arrest, the agency says it found evidence of top secret material stored in sheds at Martin’s residence:

…Investigators located hard copy documents and digital information stored on various devices and removable digital media. A large percentage of the materials recovered from Martin’s residence and vehicle bore markings indicating that they were property of the United States and contained highly classified information of the United States, including Top Secret and Sensitive Compartmented Information.

Meanwhile, the New York Times, citing senior law enforcement sources, offers further details of what may have been stolen:

The contractor arrested in recent weeks is suspected of taking the highly classified “source code” developed by the agency to break into computer systems of adversaries like Russia, China, Iran and North Korea.

If the account is correct, such a theft may suggest the contractor’s motives were espionage or profit. Snowden, by contrast, says he stole and released documents in 2013 in order to blow the whistle on what he regarded as over-reaching surveillance by the U.S. government.

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A copy of the criminal complaint, cited by Politico reporter Eric Geller, states Martin initially denied the theft but then confessed when presented with evidence by investigators of classified material at his residence and in his vehicle.

In any event, the new arrest is an embarrassing turn for the National Security Agency, and will lead to renewed questions about why the contractors it employs are able to make off with highly sensitive information. It’s also unclear how damaging the contractor’s theft would prove to U.S. intelligence gathering operations. While source code is one of the military’s most closely guarded secrets, law enforcement sources told the Times the code was dated.

This is not the first report of a “Second Snowden.” This summer, a hacker group known as the “Shadow Brokers” offered for sale on the Internet certain computer exploits reportedly developed by the NSA.

Meanwhile, Snowden remains in exile in Russia, where he has been pressing for the U.S government to extend a pardon.