Employee Stealing Intellectual Property

If an employee steal computer code from his employer, I believe the employer can bring an action against the (former) employee.

Does the District Attorney then have basis for a criminal suit against the person? Or is it solely a civil matter? What is the test that distinguishes a theft from being only civil or where there is a basis for the D.A. to file criminally?

The matter came up in a criminal action by the D.A. against Sergey Aleynikov as relates to Goldman Sachs.