Just a guess, but likely the reason Justice would get involved is Sarbane Oxley. For example.
Summary of Section 302
Periodic statutory financial reports are to include certifications that:
• The signing officers have reviewed the report • The report does not contain any material untrue statements or material omission or be considered misleading • The financial statements and related information fairly present the financial condition and the results in all material respects • The signing officers are responsible for internal controls and have evaluated these internal controls within the previous ninety days and have reported on their findings • A list of all deficiencies in the internal controls and information on any fraud that involves employees who are involved with internal activities • Any significant changes in internal controls or related factors that could have a negative impact on the internal controls
I suspect the reason the SEC and Justice are waiting until the internal audit is complete is the fact there may well be nothing to pursue. The officers of the company all know about this stuff and must sign to their knowledge the books are clean.
What do I know, but unless the Execs are fools, IF payments have been improperly made the company will simply re-state and move on.