we previously addressed this issue and found that the reasons for firing must be “sufficiently independent from the filing of the complaint to constitute legitimate and nonretaliatory reasons for discharge.” Womack v. Munson, 619 F.2d 1292, 1297 (8th Cir.1980). Further, questions related to the very substance of the investigation are “not sufficiently independent” and therefore, within the scope of the protected activity. Id. Specifically, an investigator’s “independent determination of truth or falsity of [the plaintiffs] allegation ... [can]not legally be grounds for discharge.” Id. at 1298. However, if the false statements are “not part of the protected activity,” then they can be legitimate reasons for termination. Sweeney v. City of Ladue, 25 F.3d 702, 704 (8th Cir.1994) (<HOLDING>). In this case, the investigator’s belief that
holding that a related third partys lies during an investigation were not protected activity holding that the fact that employer had knowledge of the employees protected activity was not sufficient to establish a prima facie case of retaliation where the timing of the discharge was not proximate to the protected activity holding that raising a complaint about a violation of an internal policy is not considered protected activity holding that a sixmonth gap between the protected activity and the employees termination was insufficient to infer that the protected activity was a contributing factor holding the third element of the test requires a plaintiff to show that his or her protected activity was a butfor cause of the alleged adverse action by the employer