Can a police officer obtain a warrant for the arrest of a professional narcotic peddler based solely on an informant's data?

But we need not, here, determine the full extent of Aguilar v. State of Texas. The warrant here did not rest, as did the warrant in that case, solely on the informant's data. Here, the affiant officer alleged that, acting on the tip thus received--as he had a right to do regardless of the sufficiency of that tip--he conducted his own supplementary investigation. In addition to discovering defendant's address, the officer personally observed defendant engaging in activities and maneuvers typical of the professional narcotic peddler and, on one occasion, making contact with a known addict who, briefly after the contact, was discovered to be in possession of heroin. ⁸ It is true that the actions observed were not conclusive proof of defendant's guilt--both contacts may have been quite innocent and the second person may have obtained his heroin from someone else. But the law does not require certainty, or such evidence as would be sufficient for a conviction; all that is required is that the officer have such information as would lead a reasonable man to entertain a reasonable belief in guilt. There is a strong public policy in favor of the use of warrants. [240 Cal.App.2d 511] We are cautioned: