When your job duties involve overseeing government billing, there is an extra burden to establish that you have engaged in protected activity, even though you may have called possible fraudulent activities to the attention of your boss. That is the hard lesson learned by two officials who complained to their boss about her son's double salaries. Even though terminated, they were not able to establish that they had engaged in protected activity.
Maturi v. McLaughlin Research Corp.,(1st Cir. 7/1/05) [pdf]. According to the Court it was joining several sister circuits in requiring the heightened burden as it affirmed a lower court's summary judgment dismissing the claim.