Facts
- Michael A. Riley lived in a mobile home on rural property in Florida.
- A greenhouse located within the curtilage was not visible from ground level due to its structure and surrounding vegetation.
- After an anonymous tip that marijuana was being grown on the property, a sheriff’s deputy attempted to view the greenhouse from the ground but could not.
- The deputy flew a helicopter over the property, circled twice at approximately 400 feet, and made naked-eye observations through openings in the greenhouse roof and open sides.
- The deputy concluded the plants were marijuana, obtained a warrant based on the aerial observations, searched the greenhouse, and found marijuana.
- Riley was charged under Florida law with marijuana possession.
Issues
- Whether naked-eye observation into a partially open greenhouse within the home’s curtilage from a helicopter at 400 feet constitutes a Fourth Amendment “search.”
- Whether the legality and typicality of public helicopter flight at the observation altitude affects the reasonableness of an asserted expectation of privacy.
Decision
- The Supreme Court reversed the Florida Supreme Court and held the observation was not a Fourth Amendment search.
- A plurality reasoned that the Fourth Amendment does not require a warrant for police observations from public airways at 400 feet when the observed area is visible to the naked eye.
- The plurality found Riley lacked a reasonable expectation of privacy because he left the greenhouse partially open and because helicopter flight at that altitude was lawful and routine.
- A concurring Justice agreed in the judgment but emphasized that FAA compliance is not dispositive; the relevant question is whether the public commonly uses the vantage point such that privacy expectations are not reasonable.
- Dissenting Justices would have treated the low-altitude helicopter surveillance of curtilage as a search, stressing the privacy interests in areas shielded from ground view and disputing that legality alone defeats privacy expectations.
Legal Principles
- Warrantless aerial observation of curtilage is not a “search” when officers observe with the naked eye from a lawful vantage point and the defendant lacks a reasonable expectation of privacy against such observation.
- FAA flight rules may inform, but do not control, the Fourth Amendment analysis; the key inquiry is whether the public uses the aerial vantage point with sufficient frequency to make the claimed privacy expectation unreasonable.
- Leaving an area partially exposed to aerial view can reduce an asserted expectation of privacy, even if the area is otherwise within the curtilage and shielded from ground-level observation.
Conclusion
The Court held that police did not conduct a Fourth Amendment search by viewing the interior of a partially open greenhouse within the curtilage from a helicopter at 400 feet, because the observation was from a lawful aerial vantage point and Riley lacked a reasonable expectation of privacy against such naked-eye aerial inspection.