The majority concluded that Agent Logan's investigation violated the Posse Comitatus Act, which prohibits military personnel from conducting or assisting in civilian law enforcement activities unless authorized by law.
In late 2010, NCIS Special Agent Steve Logan began investigating the distribution of child pornography online. Several months later, from his office in Georgia, Agent Logan used a software program, RoundUp, to search for any computers located in Washington state sharing known child pornography on the Gnutella file-sharing network.
Agent Logan found a computer using the Internet Protocol (IP) address 184.108.40.206 sharing several files identified by RoundUp as child pornography. He downloaded three of the files, two images and a video, from that computer. After viewing the files, Agent Logan concluded that they were child pornography.
Thereafter, Agent Logan made a request for an administrative subpoena for the name and address associated at the time of the downloads with the IP address. He submitted his request to NCIS’s representative at the National Center for Missing and Exploited Children, which turned the request over to the Federal Bureau of Investigation (FBI). The FBI sent an administrative subpoena to Comcast. Comcast responded by providing Dreyer’s name and address in Algona, Washington.
After receiving that information, Agent Logan checked a Department of Defense (DoD) database to determine if Dreyer had a military affiliation. He found that Dreyer had no current military affiliation. Agent Logan then wrote a report summarizing his investigation and forwarded it and the supporting material to the NCIS office in the state of Washington. That office then turned the information over to Officer James Schrimpsher of the Algona Police Department. (footnotes omitted).
The most notable part of the opinion comes near the end, where the majority concludes that the violation of the Posse Comitatus Act warrants the exclusion of the evidence Agent Logan obtained. From the opinion:
The extraordinary nature of the surveillance here demonstrates a need to deter future violations. So far as we can tell from the record, it has become a routine practice for the Navy to conduct surveillance of all the civilian computers in an entire state to see whether any child pornography can be found on them, and then to turn over the information to civilian law enforcement when no military connection exists.
This is squarely a case of the military undertaking the initiative to enforce civilian law against civilians. “There must be an exceptional reason” to invoke the exclusionary rule for violation of posse comitatus-like regulations, United States v. Harrington, 681 F.2d 612, 615 (9th Cir. 1982), and the broad use of military surveillance of overwhelmingly civilian populations is an exceptional reason.
Agent Logan carried out these searches repeatedly. He was monitoring another computer at the same time that he found Dreyer’s IP address. And he was involved with at least twenty other child pornography investigations. Further, Agent Logan was not the only NCIS agent who engaged in such searches. He began carrying out these searches with two other agents at least several months before he found Dreyer’s IP address. (footnotes omitted).At Just Security, Steve Vladek analyzes this portion of the opinion, noting that Judge O'Scannlain dissented in part, taking issue with the majority's conclusion that exclusion of the evidence was warranted. Vladek analyzes O'Scannlain's reasons, and notes that there is a broad question as to whether exclusion is the proper remedy for a statutory violation in light of the Supreme Court's "ever-growing hostility to the exclusionary rule." At The Volokh Conspiracy, Will Baude has additional analysis, noting that he is skeptical of the majority opinion, and highlighting various theories of the exclusionary rule that may apply, including one theory based in due process advanced by Richard Re in a recent article.
This case is certainly worth watching. If the Supreme Court is indeed engaged in a broader project of narrowing the scope of the exclusionary rule, reversing this case would be a convenient way to continue this undertaking. Additionally, this case might bring attention to the military's law enforcement activities and prompt other courts to confront the question of excluding any evidence that violates the Posse Comitatus Act. If additional courts confront this issue, their opinions may clarify the precise theory of the exclusionary rule that is in play.
UPDATE - 9/15/2014
Orin Kerr comments on the case here. He notes that Dreyer demonstrates an approach to the exclusionary rule that is similar to courts' approach in the mid 1900s and suspects that the Ninth Circuit's opinion would be "very vulnerable" if it were appealed to the Supreme Court.