## Facts

- An undercover Tucson detective posted an online advertisement seeking users interested in child pornography.
- A user account, “tabooin520,” responded and transmitted child-pornography images and videos through the Kik messaging platform.
- Investigators used a federal administrative subpoena to obtain the IP address associated with the Kik account.
- Investigators then used a federal administrative subpoena to the internet service provider (Cox Communications) to obtain basic subscriber information linked to that IP address, identifying William Mixton.
- Using the IP address and subscriber information, officers obtained a search warrant for Mixton’s home and discovered child pornography.
- Mixton was charged with twenty counts of sexual exploitation of a minor.
- Mixton moved to suppress, arguing that the Fourth Amendment and the Arizona Constitution’s “private affairs” clause (art. 2, § 8) required a warrant or court order before law enforcement could obtain the IP address and ISP subscriber information.
- The trial court denied suppression and Mixton was convicted.
- The court of appeals affirmed the convictions, concluded the Arizona Constitution was violated by obtaining subscriber information without a warrant, but declined to suppress based on good-faith reliance.
- The Arizona Supreme Court granted review to decide whether either constitution requires a warrant or court order to obtain IP addresses and ISP subscriber information through administrative subpoenas.

## Issues

1. Whether the Fourth Amendment requires a search warrant or court order before law enforcement may obtain a user’s IP address and basic ISP subscriber information held by third parties.
2. Whether Article 2, § 8 of the Arizona Constitution (“private affairs”) requires a warrant or court order before law enforcement may obtain a user’s IP address and basic ISP subscriber information by administrative subpoena.

## Decision

- The Arizona Supreme Court held that neither the Fourth Amendment nor Article 2, § 8 requires a warrant or court order to obtain a user’s IP address or basic ISP subscriber information through a lawful federal administrative subpoena.
- The court concluded that IP addresses and basic subscriber records are non-content identifiers and business records voluntarily conveyed to third-party providers.
- The court distinguished Carpenter v. United States as limited to the comprehensive and revealing nature of historical cell-site location information, unlike IP addresses and basic subscriber information.
- The court rejected the court of appeals’ determination that the Arizona Constitution was violated and affirmed Mixton’s convictions and sentences.
- Because it found no constitutional violation, the court did not rely on a good-faith exception to uphold the denial of suppression.
- A dissent argued that Article 2, § 8 provides broader protection and should require a warrant or court order for compelled disclosure of IP addresses and ISP subscriber records.

## Legal Principles

- Under the Fourth Amendment’s third-party doctrine, a person generally lacks a reasonable expectation of privacy in non-content records and identifiers voluntarily conveyed to and maintained by service providers in the ordinary course of business.
- An IP address and basic ISP subscriber information function as routing and account-identifying information, not the content of communications, and may be obtained from providers by lawful administrative subpoena without a warrant.
- Article 2, § 8 of the Arizona Constitution does not treat IP addresses or basic ISP subscriber information as part of a person’s “private affairs” when the information is disclosed to and used by an ISP as a necessary incident of providing internet service.
- Carpenter’s warrant requirement for historical CSLI does not extend to IP addresses and basic subscriber information because those records do not, by themselves, provide an exhaustive record of a person’s physical movements.

## Conclusion

The Arizona Supreme Court affirmed Mixton’s convictions, holding that law enforcement may obtain a user’s IP address and basic ISP subscriber information from third-party providers via lawful administrative subpoena without a warrant under either the Fourth Amendment or Arizona’s “private affairs” clause.


State v. Mixton, 478 P.3d 1227 (Ariz. 2021)