In United States v. Mohamud, 2012 U.S. Dist. LEXIS 151430 (Or. Oct. 22, 2012) the defendant was charged with attempt to use a weapon of mass destruction. He argued two things: (1) that evidence from an alleged date rape investigation by Oregon State Police (OSP) should be suppressed because the consent was not voluntary and the police exceeded the scope of consent, and (2) that because the OSP evidence was poisoned, the FBI's use of that evidence (since they were participating with OSP) was fruit of the poisoned tree.
The case has a number of interesting elements (I would recommend reading it), but a lot of missing info due to national security concerns. To quickly provide a synopsis of the outcome, the FBI essentially provided evidence that it would not be using any of the information from the OSP investigation against the defendant in the national security case.
Here's where it gets interesting - the defendant argued that even if the FBI wasn't going to use any evidence from OSP, what the FBI learned by participating in the OSP evidence "must have [had an effect] on the direction of the investigation, requiring suppression of all evidence obtained after an illegal search or seizure." To support this argument, the defendant attempted to invoke mosaic theory in a hail mary attempt. The defendant interviewed witnesses about mosaic theory, who explained the basics:
[T]he mosaic theory, ... the concept that while some information in specific [documents] may appear harmless to disclose when read in isolation, such information may be very valuable as part of a mosaic of information gleaned from various sources, including multiple [documents] prepared over time. The Supreme Court endorsed the mosaic theory in Sims,The only problem with this tactic is that mosaic theory, to the extent it has been injected in Fourth Amendment cases at all, has been used in analyzing individual's reasonable expectation of privacy, see e.g. Maynard (Orin Kerr has an upcoming Michigan Law Review article on mosaic theory and its place (or lack of a place) in Fourth Amendment jurisprudence). To the defendant's credit, mosaic theory has been used in the national security context, but to my knowledge, most often by the government to argue against disclosure of information under the Freedom of Information Act (FOIA) (even National Reporters Committee offers the defendant no support). The attorney get's an A for effort, but the court did not buy it:
The mosaic theory is not the standard, however, when deciding if tainted evidence must be suppressed. The mosaic theory is generally discussed in cases involving the state secrets privilege or the Freedom of Information Act ("FOIA") exemptions for intelligence sources and methods. In analyzing whether evidence is tainted, I will employ the standard explained in Smith, 155 F.3d 1051.
Thus, I must consider whether anything the FBI seized from the OSP investigation, or any leads it gained there, tended "significantly to direct" the national security investigation toward all evidence the FBI collected...My guess is that with all the attention mosaic theory has received, it was just a matter of time before it would be tried in other Fourth Amendment cases.