911 Citizen Tips and the Dual Requirement of Factual Basis and Basis of Knowledge for Reasonable Suspicion

Introduction

City of Wenatchee v. Stearns (No. 102680-3) is a 2025 Supreme Court of Washington decision clarifying when a 911 tip provides lawful grounds for a Terry stop under article I, § 7 of the Washington Constitution and the Fourth Amendment. The case arose from a July 12, 2019 911 call by David Gilliver, who reported that a man—later identified as Frank Edward Stearns—“seemed very drunk” and was “staggering all around the place” in a parking lot, then drove a black crew-cab truck, exited again and staggered. Officer Natalie BrinJones arrived minutes later, corroborated erratic driving behaviors, made a traffic stop, and ultimately arrested Stearns for DUI and related offenses.

Stearns moved to suppress all evidence from the stop for lack of reasonable suspicion. The trial court denied the motion, a superior court reversed, and an unpublished Court of Appeals majority affirmed. The City petitioned review, arguing the decision conflicted with State v. Z.U.E. (2015). This case gave the Supreme Court the opportunity to restate the two‐step tip‐based reasonable suspicion analysis, distinguish between the factual basis and the basis of knowledge, and address the reliability of modern 911 calls.

Summary of the Judgment

The Court held that the 911 tip was reliable because it was:
- A citizen’s contemporaneous eyewitness report to an emergency line.
- Made under circumstances that diminish the likelihood of fabrication (caller identified himself, remained on scene, etc.).
- Corroborated by Officer BrinJones’s own observations of weaving, near‐curb strikes, and speed fluctuations.
The Court clarified that for tip‐based reasonable suspicion:
- Factual Basis—the totality of facts (from the tip plus any officer observations) must supply specific, articulable facts and rational inferences supporting a belief that a crime is afoot.
- Basis of Knowledge—how the informant came by the facts (personal observation, hearsay, etc.) is helpful but not strictly required if reliability is shown through other indicia or corroboration.
Applying those principles, the Court concluded that the facts described by Gilliver (staggering before and after driving) plus the corroborated driving irregularities gave Officer BrinJones a sufficient factual basis for reasonable suspicion of DUI.
Accordingly, the Court reversed the Court of Appeals and reinstated Stearns’s convictions.

Analysis

1. Precedents Cited

State v. Lesnick (1975): Held that an anonymous “bare conclusion” tip without veracity or factual basis cannot justify a stop; established two paths to reliability—informant credibility or corroboration of tip details.
State v. Sieler (1980): Confirmed that corroboration of the tip’s central allegation can supply the articulable facts required for reasonable suspicion; held anonymous tips “not significantly different” from named but unknown informants pre‐911 era.
State v. Z.U.E. (2015): Reinforced that neither veracity nor basis of knowledge are absolute requirements; introduced 911‐specific reliability factors—citizen informant, contemporaneous report, emergency line rather than business line—and lowered the reliability threshold for serious, dangerous crimes.
Navarette v. California (2014 U.S. Sup. Ct.): Found anonymous 911 tip of reckless driving sufficiently reliable where the tipster was apparently eyewitness, report was contemporaneous, and used emergency line; emphasized potential public danger.
Terry v. Ohio (1968 U.S. Sup. Ct.): Established the investigatory stop exception to the warrant requirement, requiring “reasonable suspicion” grounded in “specific and articulable facts.”

2. Legal Reasoning

a. Dual‐Requirement Framework

The Court reaffirmed that tip‐based stops require a two‐part showing under the totality of the circumstances:

Tip Reliability—shown either by indicia of informant credibility or by corroboration of the tip’s central allegations.
Factual Basis for Reasonable Suspicion—even if the tip is reliable, the officer must point to specific and articulable facts (from the tip and/or the officer’s own observations) forming a substantial possibility of criminal conduct.

b. Clarifying Factual Basis vs. Basis of Knowledge

The opinion stressed that Washington case law’s imprecise use of “factual basis” and “basis of knowledge” has led to confusion. The Court definitively separated them:

Factual Basis: The required specific and articulable facts supporting reasonable suspicion—the foundation of every Terry stop. These facts may come from the tip itself, corroborating officer observations, or both.
Basis of Knowledge: How the informant obtained the facts (eyewitness perception, hearsay from a friend, inference from a mirror reflection, etc.). It is helpful but not mandatory where reliability is otherwise shown.

The Court held that once a tip’s reliability is established through credibility indicia and/or corroboration, the informant’s basis of knowledge need not be separately proven if the totality of circumstances supports reasonable suspicion.

3. Impact on Future Cases and the Law

The decision modernizes Washington’s approach to 911 tips by explicitly adopting 911‐specific reliability factors and reaffirming that citizen informants are “presumptively reliable” when reporting contemporaneous, eyewitness events to an emergency line.
By separating factual basis from basis of knowledge, the Court provides clarity to lower courts and practitioners on the precise burden for tip‐based stops.
The opinion acknowledges—but stops short of fully addressing—the growing misuse of 911 calls to target marginalized individuals. It opens the door for future challenges that raise explicit or implicit bias in 911 reporting.
Law enforcement agencies across Washington will rely on this decision to confirm that corroborated 911 tips can support Terry stops for dangerous crimes, especially DUI, while still requiring specific, articulable facts.
Defense practitioners will emphasize the factual‐basis inquiry, pressing courts to scrutinize whether the totality of facts truly adds up to reasonable suspicion and to remain alert to potential bias in citizen tips.

Complex Concepts Simplified

Reasonable Suspicion

A lower standard than probable cause; requires an officer to point to “specific and articulable facts” that make a crime “a substantial possibility.” It permits brief investigatory stops (Terry stops).

Terry Stop

Named for Terry v. Ohio (1968), it allows police to stop and briefly detain a person without a warrant if they have reasonable suspicion of criminal activity. Any evidence discovered during a lawful Terry stop may be admissible.

911 Tip

A call to the emergency line (rather than a non‐emergency business line) reporting criminal activity. Modern 911 systems can trace callers and their locations, which bolsters reliability.

Citizen Informant

An ordinary bystander unconnected to law enforcement who reports observed criminal activity for the public good, as opposed to a paid or confidential informant.

Indicia of Reliability

Circumstances or factors that support a tipster’s credibility, such as:

Known identity (not anonymous);
Eyewitness to the events;
Contemporaneous or near‐immediate report;
Use of an emergency line;
Lack of motive to lie.

Corroboration

Independent officer observations confirming key aspects of the tip (e.g., erratic driving maneuvers, speeding, weaving toward the center line).

Conclusion

City of Wenatchee v. Stearns refines Washington’s jurisprudence on tip‐based Terry stops by:

Affirming that reliable 911 “citizen tips”—where a caller’s credibility is supported by identity, eyewitness status, contemporaneity, and emergency‐line use—can supply the basis for reasonable suspicion.
Clarifying that a factual basis (the specific facts and rational inferences) is always required, drawn from the tip itself, officer corroboration, or both.
Confirming that the informant’s basis of knowledge (how they got their information) is helpful but not a separate constitutional prerequisite if reliability is otherwise established.

By reinstating Stearns’s convictions, the decision signals to law enforcement and defense attorneys alike that while 911 tips remain a powerful tool for detecting imminent public dangers (such as DUI), courts must still demand specific, articulable facts before authorizing intrusions into private movement and privacy. This balanced approach safeguards the public while preserving robust privacy protections under Washington’s constitution.