State of Arizona v. Ronald James Sisco II, 239 Ariz. 532

Background

In March 2013 Tucson police smelled an "overpowering odor of fresh marijuana" coming from a storage-warehouse complex and believed it came from Unit 18; a telephonic warrant for Unit 18 was issued but that unit was vacant. An amended warrant for Unit 20 (adjacent unit) was obtained after officers re-assessed the odor; Unit 20 contained a residence and a large marijuana grow operation. Ronald Sisco, an occupant, was arrested and charged with child abuse, possession for sale, production of marijuana, and paraphernalia offenses.
Sisco moved to suppress evidence, arguing that after the Arizona Medical Marijuana Act (AMMA) the odor (or sight) of marijuana alone cannot establish probable cause; the trial court denied suppression and Sisco was convicted.
The court of appeals reversed in a split decision, adopting an "odor plus" rule (odor alone insufficient without additional contextual facts).
The Arizona Supreme Court granted review to decide whether AMMA changed the probable-cause analysis when an officer detects the odor of marijuana.
The Supreme Court held that the odor (or sight) of marijuana still establishes probable cause unless other facts would lead a reasonable person to conclude the possession/use is authorized by AMMA (an "odor (or sight) unless" standard). The Court affirmed denial of suppression on the facts: no indicia suggested AMMA-compliant possession, and Sisco was not a registered qualifying patient.

Issues

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether odor of marijuana alone can establish probable cause after AMMA	State: odor still indicates a fair probability of criminal activity because AMMA creates limited exceptions only	Sisco: AMMA requires more — odor alone insufficient; requires "odor (or sight) plus" additional facts	The odor (or sight) generally establishes probable cause unless other facts indicate AMMA-compliant use ("odor (or sight) unless")
Whether AMMA changed the probable-cause standard for registered qualifying patients	State: AMMA gives limited immunities but does not create broader protection from searches	Sisco: registered patients should have greater protection; odor alone would imperil privacy of lawful patients	Rejected: registered patients are not insulated from warrant-based searches; AMMA indicia (e.g., registry card) may dispel probable cause but do not raise the baseline standard
Whether officers/magistrates must consider indicia of AMMA compliance when seeking/issuing warrants	Sisco: police must treat AMMA indicia as potentially dispositive; ignoring them is improper	State: officers should consider known exculpatory facts but odor still probative absent such indicia	Held: totality of circumstances requires considering known, material indicia of AMMA compliance; omissions of such material facts can vitiate probable cause
Application to facts (search of Unit 20)	Sisco: odor insufficient; court of appeals erred to reverse convictions	State: officers had probable cause and no indicia of lawful AMMA possession	Held: probable cause existed here — overpowering odor, large grow operation, and no evidence of AMMA authorization; suppression properly denied

Key Cases Cited

Florida v. Harris, 133 S. Ct. 1050 (Sup. Ct.) (probable cause standard is practical, common-sense; fair probability suffices)
Illinois v. Gates, 462 U.S. 213 (U.S. 1983) (probable cause determined from totality of circumstances; innocent behavior can form basis for probable cause)
Horton v. California, 496 U.S. 128 (U.S. 1990) (plain view seizure requires probable cause that item is incriminating)
State v. Decker, 119 Ariz. 195 (Ariz. 1978) (officer’s sense of smell can establish probable cause for marijuana)
State v. Buccini, 167 Ariz. 550 (Ariz. 1991) (police must include material exculpatory facts in affidavits; omissions can be material)
Reed-Kaliher v. Hoggatt, 237 Ariz. 119 (Ariz. 2015) (AMMA makes medical marijuana lawful in limited circumstances)