The Ninth Circuit Court of Appeals is the latest appeals court to find the FBI's warrant for malware deployment during a child porn investigation to be invalid, but still close enough for government work. The FBI's NIT (Network Investigative Technique) was sent to visitors of a dark web child porn site called Playpen. The hitchhiking software then traveled out of the district the server was housed in (Virginia) to send back identifying info from computers and devices all over the world.

At the time the warrant was sought, warrants were only valid in the district they were issued. Multiple courts found the FBI's malware was a search under the Fourth Amendment. A smaller subset found the extrajurisdictional search unsupported by current law and the underlying warrant invalid from the moment it was issued. Challenges to the extrajurisdictional searches have all run into dead ends at the appellate level.

The First, Eighth, and Tenth Circuits have all refused to suppress evidence, even if the courts found the search warrant invalid. The reasoning? There was no deterrent effect served by suppressing the evidence because the law changed after the warrant was issued and the malware deployed to allow the FBI to engage in extrajurisdictional searches. In essence, this is retroactive application of a law that changed after the warrant was sought, giving it the sort of blessing courts won't extend to victims of law enforcement misconduct that happened to occur before precedential decisions explicitly declared that particular form of misconduct unconstitutional.

In addition to the retroactive application of Rule 41 jurisdictional changes, these appeals courts have also granted the government "good faith." Somehow, it's believed an FBI agent seeking a warrant for a search that he knew would violate Rule 41 limits when executed wasn't the FBI rolling the dice on favorable rulings and a potential future mooting by changes to the law.

There's more of the same in the Ninth Circuit decision [PDF]. The court says the warrant was bad but the faith was good, so no harm, no foul, no suppression. (h/t Brad Heath)

We agree with Henderson that Rule 41(b) is not merely a technical venue rule, but rather is essential to the magistrate judge's authority to act in this case.

[...]

The Federal Magistrates Act, 28 U.S.C. § 636, defines the scope of a magistrate judge's authority, imposing jurisdictional limitations on the power of magistrate judges that cannot be augmented by the courts.

[...]

Relevant here, § 636 authorizes magistrate judges to exercise "all powers and duties conferred or imposed" by the Federal Rules of Criminal Procedure. 28 U.S.C. § 636(a)(1). In turn, Rule 41(b) has been asserted as the sole source of the magistrate judge's purported authority to issue the NIT warrant in this case. But, as we have explained, in issuing such warrant, the magistrate judge in fact exceeded the bounds of the authority conferred on magistrate judges under Rule 41(b). Thus, such rule plainly does not in fact confer on the magistrate judge the authority to issue a warrant like the NIT warrant. Without any other source of law that purports to authorize the action of the magistrate judge here, the magistrate judge therefore exceeded the scope of her authority and her jurisdiction as defined under § 636.

Thus endeth the bad news for the government -- bad news severely tempered by the fact the government still gets to keep its evidence. Even though the court recognizes the warrant was invalid the moment it was signed, it still gives the government points for effort. The Ninth says it's ok for law enforcement to rely on invalid warrants, so long as they've been signed by a magistrate. And good faith or not, the court says there's no reason to suppress the evidence because the house always wins there's no future misconduct to deter.