State v. McLeod., 424 P.3d 1039

Officer on rooftop surveillance in a high‑crime area observed, with binoculars, a close hand‑to‑hand exchange about 65–70 yards away: McLeod handed green paper and received a small black item removed from the other man’s mouth, which McLeod pocketed.
The officer was an experienced narcotics investigator (≈1,000 drug stops, narcotics training) and believed the conduct was a drug transaction and that the black item was a drug "twist."
Officer intercepted and arrested McLeod, partly because the officer mistakenly believed an arrest warrant remained outstanding from an earlier proceeding (the warrant had in fact been recalled).
During a search incident to that arrest, officer discovered heroin, cocaine, and a syringe; McLeod was charged with controlled‑substance and paraphernalia offenses.
McLeod moved to suppress arguing the observations supported, at most, reasonable suspicion (not probable cause) and that arrest on a recalled warrant was not in good faith; district court denied suppression, finding objective probable cause from the observed exchange.
McLeod pleaded guilty to a misdemeanor preserving the suppression issue on appeal; the Court of Appeals affirmed the denial of the motion to suppress.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether officer had probable cause to arrest based on observed hand‑to‑hand exchange	McLeod: observation from distance and uncertain nature of items supports only reasonable suspicion, not probable cause	State: experienced officer’s observation of money exchanged for a small item taken from mouth in drug‑prone area, viewed with binoculars, gave rise to probable cause	Court: Held probable cause existed under the totality of circumstances; arrest lawful
Whether officer’s subjective, mistaken belief in outstanding warrant invalidates arrest	McLeod: arrest was tainted by reliance on a recalled warrant; lack of good faith requires suppression	State: any subjective motive irrelevant if arrest objectively supported by probable cause	Court: Held subjective belief irrelevant when objective probable cause exists; did not reach good‑faith warrant issue

Atwater v. City of Lago Vista, 532 U.S. 318 (warrantless arrest permissible when officer has probable cause for an offense committed in officer’s presence)
Michigan v. DeFillippo, 443 U.S. 31 (probable cause defined by facts and circumstances to warrant prudent person belief)
Texas v. Brown, 460 U.S. 730 (probable cause does not require certainty or being more likely true than false)
Illinois v. Wardlow, 528 U.S. 119 (high‑crime area is a relevant contextual factor in stop analysis)
State v. Anderson, 316 P.3d 949 (Utah App. Ct.) (distinguishing reasonable suspicion from probable cause in hand‑to‑hand exchange context)
State v. Harker, 240 P.3d 780 (Utah 2010) (evidence obtained incident to a lawful arrest need not be excluded)