What is the impact of independent police work on the determination of probable cause?

Independent police work here did not corroborate any suspicious activity or confirm future actions not easily predicted. As in Higgason, "[t]he totality of the circumstances presented by this affidavit do not show 'a fair probability that contraband or evidence of a crime will be found in a particular place.' (Illinois v. Gates, supra, 462 U.S. 213, 238, 103 S.Ct. 2317, 2332.) '[T]he magistrate had [no] "substantial basis for ... conclud[ing]" that probable cause existed. [Citation.]' [Citation.]" (Higgason v. Superior Court, supra, 170 Cal.App.3d at p. 941, fn. omitted, 216 Cal.Rptr. 817.)