WASHINGTON —The arrest of a National Security Agency contractor for allegedly stealing classified information was the second known case of a government contractor being publicly accused of removing secret data from the intelligence agency since 2013.

The latest arrest came despite efforts to reform security after the Edward Snowden disclosures, especially in regards to insider threats.

Harold Thomas Martin III, 51, of Glen Burnie, Maryland, was arrested by the FBI in August after federal prosecutors say he illegally removed highly classified information and stored the material in his home and car. A defense attorney said Martin did not intend to betray his country.

The arrest was not made public until Wednesday, when the Justice Department released a criminal complaint that accused Martin of having been in possession of top-secret information that could cause “exceptionally grave danger” to national security if disclosed.

The fact that Snowden and now Martin – both working for Booz Allen Hamilton as contractors for NSA – were able to leave the NSA with highly classified documents, especially given the supposed security upgrades put into place, begs the question as to whether the intelligence agency’s efforts to tighten internal security afterward were effective or adequate. The NSA declined to comment.