Justice Dept. probing Booz Allen Hamilton's accounting

Defense and spy-agency contractor Booz Allen Hamilton says the Justice Department is investigating its accounting and the way it charges the government.

The disclosure in a regulatory filing sent shares of Booz Allen Hamilton Holding Corp. tumbling almost 19 percent in Friday trading.

Booz Allen said its own auditing hasn't found any major erroneous costs or problems, and that it's cooperating with the Justice Department's civil and criminal investigations.

The company, based in McLean, Virginia, is one of the biggest U.S. defense and intelligence-agency contractors. Several of its executives either previously worked for the government or left the company to take high-level government positions.

Booz Allen received unwanted publicity in 2013 after revelations that its employee Edward Snowden took and shared documents about secret U.S. surveillance programs.

Booz Allen's stock recovered after taking a hit from the Snowden episode, and the company didn't suffer any long-term damage.

Last October, federal prosecutors charged another Booz Allen contractor with stealing classified information from the National Security Agency. The Justice Department said Harold T. Martin III's theft of top-secret government information was "breathtaking" in its duration and scope.

Martin's attorneys have argued that the former U.S. Navy lieutenant was merely a compulsive hoarder and a voracious learner who got carried away, taking home documents in a misguided effort to be more skilled at his job.