In Guzman v. State, 955 S.W.2d 85 (Tex. Crim. App. 1997), the Court held that a probable cause ruling should be reviewed de novo. The Court examined the applicable standard for review of a probable cause determination, setting out the following guidelines: The amount of deference a reviewing court affords a trial court's ruling on a "mixed question of law and fact" (such as the issue of probable cause) is often determined by which judicial actor is in a better position to decide the issue. The appellate courts, including this Court, should afford almost total deference to a trial court's determination of the historical facts that the record supports especially when the trial court's fact findings are based on an evaluation of credibility and demeanor. The appellate courts, including this Court, should afford the same amount of deference to trial courts' rulings on "application of law to fact questions," also known as "mixed questions of law and fact," if the resolution of those ultimate questions turns on an evaluation of credibility and demeanor. The appellate courts may review de novo "mixed questions of law and fact" not falling within this category. Guzman, 955 S.W.2d at 87, 89.