(2) The complaint, supplemented as appropriate by interviews of the complainant, must allege the existence of facts and evidence to make a prima facie showing as follows:
- (i) The employee engaged in a protected activity, either actual activity or activity about to be undertaken;
- (ii) The respondent knew or suspected, actually or constructively, that the employee engaged in the protected activity;
- (iii) The employee suffered an adverse action; and
- (iv) The circumstances were sufficient to raise the inference that the protected activity was a contributing factor in the adverse action.