(a) A public employee who sues under this chapter has the burden of proof, except that if the suspension or termination of, or adverse personnel action against, a public employee occurs not later than the 90th day after the date on which the employee reports a violation of law, the suspension, termination, or adverse personnel action is presumed, subject to rebuttal, to be because the employee made the report.
(b) It is an affirmative defense to a suit under this chapter that the employing state or local governmental entity would have taken the action against the employee that forms the basis of the suit based solely on information, observation, or evidence that is not related to the fact that the employee made a report protected under this chapter of a violation of law.