Booz Allen, a consulting firm that earns billions of dollars by working for American intelligence agencies, has been called the world's most profitable spy organization. News this week of Mr. Martin's arrest in August could renew scrutiny of the firm's operations and, more broadly, the lucrative contracting business that American intelligence now relies on to run its vast, global surveillance operations.

Mr. Martin's arrest is the second time in three years that a Booz Allen contractor has been accused of stealing potentially damaging material from the N.S.A. The company also employed Edward J. Snowden, who spirited out a cache of documents that, in 2013, exposed the extent of American surveillance programs in the United States and around the world.

Booz Allen is one of a handful of defense and intelligence contractors that blur the line between the government's intelligence work and private enterprise.