When Is a Dog Sniff at an Apartment Door a “Search”?
- Scott Courrege
- Aug 8
- 3 min read
Updated: Aug 23
United States v. Johnson, No. 23-4255, 4th Cir. (Aug. 5, 2025)
Summary
Holding: A warrantless dog sniff at the door of an apartment in a common hallway was not a Fourth Amendment “search” under either the reasonable-expectation-of-privacy test or the property-based “curtilage” test.
Why it matters: Officers may conduct a canine sniff in an apartment hallway—if it’s a true common area without a tenant’s right to exclude—without a warrant.
Key limits: This ruling is only binding in the U.S. 4th Circuit; it is very fact-specific; different building layouts or access rules could change the analysis.
Facts
In 2019, a joint federal–local narcotics task force in Maryland suspected Eric Tyrell Johnson of trafficking fentanyl and heroin from his apartment (Unit 201) in a multi-unit building.
Before seeking a search warrant, officers—at about 3:00 a.m.—entered the secured building with management’s permission and had a certified drug-detection dog conduct a “free-air sniff” outside Johnson’s door.
The dog alerted at the lower seam of the door.
The alert was cited in a warrant application. The resulting search recovered:
Heroin–fentanyl mixture
A handgun and ammunition
Cell phones, cash, and drug-distribution paraphernalia
Johnson moved to suppress, arguing the dog sniff was an unconstitutional search.
Issues
Reasonable Expectation of Privacy: Did the dog sniff violate Johnson’s privacy by revealing details of his home otherwise unknowable without entry (like Kyllo’s thermal-imaging scenario)?
Property-Based “Curtilage” Theory: Was the hallway immediately outside his apartment door constitutionally protected “curtilage” under Florida v. Jardines?
Court’s Decision (Holding)
The Fourth Circuit affirmed the denial of suppression:
No reasonable-expectation violation: Following United States v. Place and Illinois v. Caballes, a dog sniff that only detects the presence or absence of contraband does not violate a legitimate privacy interest—regardless of whether it’s at a home, luggage, or vehicle.
No intrusion on curtilage: The hallway was a common area regularly used by residents, staff, and others admitted by management. Johnson had no property right to exclude them; therefore, it was not part of the home’s protected curtilage.
Reasoning
1. Dog Sniffs and Privacy
The Court applied Place and Caballes categorically:
Dog sniffs are unique because they reveal only contraband—no legitimate privacy interest exists in contraband.
The rule does not depend on whether the sniff occurs at a car, luggage, or home.
Justice Kagan’s concurrence in Jardines, which viewed such sniffs at a home as invasive, has not been adopted by a majority.
2. Curtilage Analysis
Under United States v. Dunn, factors include:
Proximity to home
Inclusion within enclosure
Use of area
Steps to shield from observation
Although the sniff occurred inches from Johnson’s door, proximity alone is not enough.
Key factor: Right to exclude. Johnson could exclude others from his apartment interior, but not from the hallway.
Hallway access was routinely granted to non-residents by management.
The Court aligned with a “majority approach” nationwide: shared hallways in multi-unit dwellings usually aren’t curtilage.
Street Takeaways for Law Enforcement
Common hallways are fair game: If truly shared and without tenant control, a canine sniff there generally won’t be a Fourth Amendment “search.”
Get permission: Management consent can strengthen lawful access—document it.
Layout matters: Townhouse stoops, semi-private porches, or gated vestibules could be treated differently if a resident has the right to exclude others.
Time & manner: While the 3:00 a.m. timing wasn’t an issue here, always consider reasonableness and avoid conduct that could be viewed as harassment or trespass.
Know your jurisdiction: Some states (e.g., Illinois in People v. Bonilla) have reached opposite results under their own constitutions.
Disclaimer
This article is for training and informational purposes only. It is not legal advice. Laws and court interpretations vary by jurisdiction and may change. Officers should consult agency counsel or local prosecutors before applying these principles in the field.
