What is the test of probable cause and what is the impact of expert opinion on the test?

The test of probable cause 'should not be understood as placing the ordinary man of ordinary care and prudence and the officer experienced in the detection of narcotics offenders in the same class. Circumstances and conduct which would not excite the suspicion of the man on the street might be highly significant to an officer who had had extensive training and experience in the devious and cunning devices used by narcotics offenders to conceal their crimes.' (People v. Williams, 196 Cal.App.2d 726, 728, 16 Cal.Rptr. 836, 837.)

Cunha v. Superior Court, 2 Cal.3d 352, 85 Cal.Rptr. 160, 466 P.2d 704 is inapposite. There the court simply found that the facts were not such as to be susceptible of any expert interpretation.

Furthermore, the officer here did not act upon his own opinion but presented it to a magistrate for his evaluation, an action which the exclusionary rule is designed to encourage. (People v. Castro, supra, 249 Cal.App.2d at 175, 57 Cal.Rptr. 108.)

In sustaining this warrant we give effect to the 'preference accorded police action taken under a warrant * * *' so vigorously proclaimed in United States v. Ventresca, 380 U.S. 102, 107, 85 S.Ct. 741, 745, 13 L.Ed.2d 684.