An employer shall not discharge or in any other manner discriminate against an employee because the employee has filed a complaint or brought an action under this section or has cooperated in bringing an action against an employer. An employee may file a complaint with the labor commissioner alleging discharge or discrimination within thirty days after an alleged violation occurs. Upon receipt of the complaint, the commissioner shall cause an investigation to be made to the extent the commissioner deems appropriate. If the commissioner determines from the investigation that this section has been violated, the commissioner shall bring an action in the appropriate district court against the person. The district court has jurisdiction, for cause shown, to restrain violations of this section and order appropriate relief including rehiring or reinstatement of the employee to the former position with back pay. This section applies to an employee of a person otherwise exempt from this chapter.