District court’s suppression of evidence seized pursuant to warrant upheld because the “bare bones” affidavit in support of the search warrant lacked probable cause. Defendant was charged with federal drug offenses. In district court he moved to suppress the evidence of drug trafficking based on the lack of probable cause in the affidavit in support of the search warrant. The district court granted defendant’s motion and the prosecution appealed. Held: Affirmed. A search warrant is supported by probable cause if the affidavit in support of the warrant provides a substantial basis for a judge to conclude there is a fair probability that evidence of a crime or contraband will be found in a particular place. However, conclusions drawn by the affiant which are not supported by underlying facts do not provide probable cause; the conclusions must be drawn by the issuing judge based on the facts recited in the warrant. The affidavit here included “only two facts, foundationless expert opinion, and conclusory allegations.” The facts, regarding defendant’s possession of a personal-use quantity of marijuana and delivering a package on one occasion to a codefendant, did not provide evidence of drug trafficking. Under the totality of the circumstances, the affidavit failed to establish probable cause and was defective under the Fourth Amendment. The good faith exception (U.S. v. Leon (1984) 468 U.S. 897), did not apply because the affidavit was “so lacking in indicia of probable cause [a ‘bare bones’ affidavit] as to render official belief in its existence entirely unreasonable.”