William O. Douglas

“ With all deference, the present affidavit seems hopelessly inadequate to me as a basis for a magistrate's informed determination that a search warrant should issue.
We deal with the constitutional right of privacy that can be invaded only on a showing of 'probable cause' as provided by the Fourth Amendment. That is a strict standard; what the police say does not necessarily carry the day; 'probable cause' is in the keeping of the magistrate. ”

“ Such being the case, I see no way to avoid the conclusion of the majority below: 'If hearsay evidence is to be relied upon in the preparation of an affidavit for a search warrant, the officer or attorney preparing such an affidavit should keep in mind that hearsay statements are only as credible as their source and only as strong as their corroboration. And where the source of the information is in doubt and the corroboration by the affiant is unclear, the affidavit is insufficient.' Id., at 869-870. ”

“ But unless the constitutional standard of 'probable cause' is defined in meticulous ways, the discretion of police and of magistrates alike will become absolute. The present case, illustrates how the mere weight of lengthy and vague recitals takes the place of reasonably probative evidence of the existence of crime. ”