State v. Pennington | Geofence Warrants and Good Faith

Executive Summary

Why this case matters

Pennington is primarily a good-faith decision. It should not be cited as conclusively resolving whether the challenged geofence warrant satisfied probable cause, particularity, and breadth requirements.

Police investigating an aggravated burglary used a geofence warrant tied to surveillance-video evidence concerning the suspect’s movement. The initial return identified one device moving consistently with the suspect. Investigators then obtained two additional Google warrants for more information and eventually searched Pennington’s home and cellphone.

The trial court considered the initial geofence affidavit deficient because it did not specifically show that the perpetrator possessed or used a cellphone. It also found the later warrants overbroad. Nevertheless, it admitted the evidence under United States v. Leon.

The Kansas Court of Appeals affirmed on good-faith grounds. The applications were not so bare-bones that reliance was entirely unreasonable. The court found at least a minimal nexus based on widespread cellphone carriage, the crime facts, the tailored initial boundary and timeframe, and the later discovery that one device followed the suspect’s observed route.

The Investigation

The prosecution arose from an aggravated burglary, aggravated assault, and stalking investigation. Surveillance recordings documented the suspect’s movements and helped investigators define the relevant locations and periods.

A detective trained in geofence warrants sought Google location-history information associated with the crime scene and timeline. The first return identified a single device whose movement corresponded with the suspect’s movements shown across surveillance videos.

Investigators used that information to support additional Google warrants and ultimately obtained a warrant for Pennington’s residence and physical cellphone.

The Three Challenged Google Warrants

Initial geofence warrant: sought devices reflected within a geographic boundary and time period derived from the investigation and surveillance evidence.
Follow-up warrant: sought expanded information after one device appeared to travel with the suspected offender.
Identification warrant: sought additional Google data used to connect the device and investigation to Pennington.

Pennington challenged the first warrant for lack of a sufficient cellphone nexus and challenged the later warrants as overbroad and derivative of the first.

The Trial Court’s Ruling

The district court found the initial affidavit deficient because it did not articulate why this perpetrator probably possessed or used a cellphone during this crime. It also concluded that the second and third warrants were insufficiently narrowed and that their fruits flowed from the initial warrant.

Despite those conclusions, the court applied the Leon good-faith exception on its own initiative. It reasoned that geofence law remained new and unsettled, the detective relied on training and experience, and two judges had approved the warrants.

Holding

The dispositive rule

Even assuming the warrants were constitutionally deficient, the evidence remained admissible because the officers’ reliance on the issued warrants was objectively reasonable. The affidavits contained at least the minimal nexus necessary to avoid characterization as bare-bones applications.

The appellate court could evaluate good faith as a legal issue even though the State had not originally raised it and the trial judge had invoked it sua sponte.

The Cellphone Nexus

The initial affidavit stated that most people carry cellular devices nearly all the time. The appellate court considered that proposition in light of Supreme Court observations in Riley and Carpenter regarding the pervasive and persistent role of cellphones in daily life.

The court held that the application established at least a minimal nexus sufficient for good-faith analysis. It suggested the showing might support probable cause itself, but expressly left that broader constitutional question for another case.

Drafting caution

A generalized assertion that most people carry phones should not be treated as an ideal or universally sufficient nexus. Applications should identify case-specific evidence whenever available: video showing a phone, communications surrounding the offense, use of navigation or applications, witness observations, device-dependent conduct, or a crime pattern making cellphone possession especially probable.

Why Good Faith Applied

The court emphasized several circumstances supporting objectively reasonable reliance:

Geofence warrants remained a novel technique without settled Kansas precedent.
The detective had training and prior experience preparing geofence applications.
The initial geography and timeframe were tied to surveillance video and known vehicle movement.
The first return produced only one device that tracked the suspect’s observed path.
The later applications incorporated information learned from earlier judicially approved process.
No evidence suggested that officers misled the judges or that the judges abandoned their neutral role.
The warrants were not so facially unspecific that officers could not identify what to search or seize.

Suppression is a separate question

A warrant can be constitutionally vulnerable yet produce admissible evidence when officers acted in objectively reasonable reliance. Agencies should still correct drafting defects; good faith is not an operational substitute for probable cause and particularity.

What the Decision Does—and Does Not—Establish

Important limits

The appellate court assumed warrant deficiencies for purposes of its analysis rather than finally deciding every constitutional challenge.
The decision does not hold that a statement about widespread cellphone ownership always establishes probable cause.
It does not approve unrestricted requests for “all data” or unnecessarily broad follow-up warrants.
The holding turns on the federal exclusionary rule and objective good faith, not categorical validation of geofence warrants.
The court noted the absence of Kansas precedent and the novelty of the technique—conditions that diminish as more appellate decisions provide notice.
Future officers may receive less protection from good faith after controlling law clearly identifies prohibited warrant designs.
State constitutional law, statutes, provider architecture, and current technology may require separate analysis.

Agency Guidance

1. Establish a case-specific phone nexusExplain why the offender probably carried or used a device during this offense; do more than rely on population-wide assumptions when facts are available.

2. Tie boundaries to evidenceExplain how video, witness accounts, access routes, physical layout, and the offense timeline define the smallest reasonable geofence.

3. Justify every time periodDescribe the known event window and the factual basis for any period before or after it.

4. Limit later-stage expansionDo not request “all data” without explaining why each category and period is necessary.

5. Return to the judgeUse staged judicial review before obtaining expanded histories or subscriber identities when practicable or required.

6. Preserve the complete processMaintain applications, warrants, provider communications, anonymized returns, selection decisions, expanded data, and audit records.

7. Document training and consultationRecord reliance on current templates, prosecutors, agency counsel, training, and jurisdiction-specific precedent.

8. Do not plan around good faithDraft for constitutional validity. Treat exclusionary-rule exceptions as litigation doctrines, not warrant-design standards.

Primary Sources and Further Reading

Primary opinion: State v. Pennington, No. 127,168 (Kan. Ct. App. Jan. 23, 2026).

Good-faith doctrine: United States v. Leon.

Geofence authority: Chatrie v. United States.