Story highlights Audit to be released on security at Navy Yard, other installations

Problems uncovered include felons gaining access to installations, source says

Monday's shootings prompt congressman to ask about the audit

A government audit on Navy security found that the Navy Yard and other installations may have increased security risks in an effort to reduce costs, a federal source told CNN.

"Navy installations command attempted to reduce access control costs," according to a soon-to-be-released report from the Department of Defense Inspector General. The source read CNN portions of the report. "As a result, at least 52 convicted felons received routine unauthorized installation access, placing military personnel at increased security risk."

The audit covered "a variety" of military installations, of which Navy Yard was one, according to the federal source with access to the report. The source shared the information on the condition of anonymity because the report has not yet been officially released.

In the wake of the shooting on Monday , Rep. Mike Turner, R-Ohio, a member of the Armed Services Committee, sent a letter to the Pentagon inspector general demanding he brief members of Congress on the Navy security audit.

"It is my understanding that the IG report indicates the Navy may have implemented an unproven system in order to cut costs," read the letter, first obtained by CNN. "I also learned that potentially numerous felons may have been able to gain restricted access to several military installations across the country due to insufficient background checks, increasing the risk to our military personnel and civilian employees."

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According to a memo announcing the launch of the audit posted on the Department of Defense Inspector General website, the investigation began in September 2012.

"Our objective is to determine whether the Navy Commercial Access Control System (NCACS) is mitigating access control risks to Navy installations. We will consider suggestions from management on additional or revised objectives," the memo said.

In August 2013, the inspector general posted an update saying the report would be published "within the next 30 days."