WASHINGTON — The National Security Agency on Thursday released what it said was the sole internal email from Edward J. Snowden before he fled with a trove of agency secrets, and officials asserted that the message undercut his argument that he protested the legality of surveillance programs before he released any of the documents he stole to journalists.

The email to the N.S.A. general counsel’s office, dated April 8, 2013, makes no reference to the government’s bulk collection of telephone data or other surveillance or cyberprograms. Nor does it raise concerns about violations of privacy.

Instead, Mr. Snowden was seeking clarification about the hierarchy of laws governing the N.S.A., based on what he had learned in an agency training course about privacy protection rules for handling intercepted information.

By the time the email was sent, Mr. Snowden, who was a private contractor and not an agency employee, had already implanted software in the N.S.A. system that was copying its files automatically. Two months later, the first of those files were made public by journalists who had received them from Mr. Snowden.