No employee in the classified civil service who has been permanently appointed, shall be dismissed except for cause. A written statement of the cause of dismissal, in general terms, shall be served upon the dismissed employee and a duplicate filed with the board. A dismissal may be made without any hearing but any employee so removed may, within 10 days thereafter, file with the board a written demand for investigation. If the demand alleges, or it otherwise appears to the board, that the discharge or removal was for political or religious reasons, or for reasons of age as described in ORS Chapter 659A, or was because of personal favoritism or was not in good faith nor for the purpose of improving the public service, an investigation shall be held by the board or by persons appointed by them and under their direction. [Amended by 1959 c.689 § 11; 1977 c.770 § 10; 2001 c.621 § 75]