In Anderson v. Creighton (1987) 483 U.S. 635, the United States Supreme Court "emphasized that qualified immunity questions should be resolved at the earliest possible stage of a litigation." ( Id. at p. 646, fn. 6.) Summary judgment is an appropriate stage in the proceedings to determine whether a police officer is entitled to qualified immunity. (Ibid.) There, the court held that in determining whether a police officer is entitled to qualified immunity from civil liability, the inquiry is whether, in light of clearly established principles governing searches, a police officer could reasonably (even if mistakenly) have believed that his or her conduct was lawful. ( Id. at p. 641.) In making this determination the Anderson court cautioned that: "The contours of the right alleged to have been violated must be sufficiently clear that a reasonable official would understand that what he is doing violates that right. That is not to say that an official action is protected by qualified immunity unless the very action in question has previously been held unlawful, ; but it is to say that in the light of pre-existing law the unlawfulness must be apparent. " ( Id. at p. 640.)