## Facts

- Vermont law enforcement investigated Frank Caraballo for narcotics trafficking and used controlled buys with undercover agents and confidential informants.
- An associate, Melissa Barratt, was arrested and identified Caraballo as involved; she reported fear that he would harm or kill her if he learned she cooperated and stated he had access to firearms and a history of violence.
- Police later found Barratt’s body in a remote wooded area; she had been shot in the back of the head in an execution-style manner.
- Based on contemporaneous reports of a gunshot-like sound, officers believed the killing had occurred that morning and that the assailant could still be armed.
- Officers focused on Caraballo as the primary suspect and feared retaliation against undercover agents and informants if the investigation had been compromised.
- Without a warrant, officers made an emergency request to Caraballo’s cellular provider to obtain real-time GPS coordinates (“ping”) over a limited period (about two hours).
- The provider supplied location information, officers located Caraballo’s phone, and they arrested him later that day.
- Caraballo moved to suppress evidence obtained after arrest, arguing the warrantless ping violated the Fourth Amendment; the district court denied suppression based on exigent circumstances, and Caraballo appealed.

## Issues

1. Whether obtaining real-time GPS location information by warrantless “pinging” of a suspect’s cell phone constitutes an unreasonable search under the Fourth Amendment.
2. Whether exigent circumstances or the emergency-aid/public-safety doctrine justified the warrantless ping under the specific facts.
3. Whether the scope and duration of the warrantless location tracking were sufficiently limited to be reasonable.

## Decision

- The Second Circuit affirmed the denial of the suppression motion.
- Assuming for analysis that the warrantless ping was a Fourth Amendment “search,” the court held it was reasonable because exigent circumstances existed.
- The court found officers had an objectively reasonable basis to believe immediate action was necessary to protect life and prevent further violence, given the recent execution-style killing, the likelihood the suspect was still armed, and the perceived immediate risk to undercover agents and informants.
- The court emphasized the limited nature of the intrusion: a short, targeted request used to locate and arrest the suspect rather than long-term tracking.
- The court upheld the challenged convictions tied to the suppression ruling and noted other appellate matters were resolved separately, including dismissal of an attempted appeal for lack of jurisdiction in a related case.

## Legal Principles

- A warrantless search may be reasonable under the Fourth Amendment when exigent circumstances exist, including where officers reasonably believe immediate action is needed to protect life or safety.
- Real-time cell-phone location acquisition, even if treated as a search, may fall within the exigent-circumstances/emergency-aid exception when supported by specific, articulable facts showing an ongoing emergency.
- Reasonableness under exigency considers objective facts known to officers at the time, not post hoc certainty.
- The scope and duration of a warrantless intrusion matter; a narrowly tailored, short-term location ping used to address an immediate safety threat is more likely to be upheld than broad or prolonged tracking.
- Suppression is not warranted where officers act reasonably within a recognized Fourth Amendment exception and the intrusion is limited to addressing the emergency.

## Conclusion

The court held that police could lawfully obtain real-time GPS coordinates of a suspect’s phone without a warrant when specific facts supported an objectively reasonable belief that a recent murder created an immediate threat to others, and the officers used a brief, targeted ping to locate and arrest the suspect.


United States v. Caraballo, 831 F.3d 95 (2d Cir. 2016)