Well, I have been doing some more reading. Th author of that article left something out that we have been guessing about, "why did the accused take his computer to Best Buy and what was the Geek Squad tech doing that he found the file?"
http://www.ocweekly.com/news/best-b...has-fbi-on-defense-in-child-porn-case-7794252
So the accused took his computer to Best Buy to have Geek Squad recover all of his computer files. It does not say why he needed these files recovered, and I have yet to see a comment on whether this image is the only one that qualifies as Child Porn.
As for the claims of illegal searches;
When the tech found the Jenny file, he reported it to his company supervisor who reported this to the FBI. The FBI seized the hard drive.
http://www.ocweekly.com/news/best-b...has-fbi-on-defense-in-child-porn-case-7794252
Now the tech and Best Buy are required by law to report what they found and the image is illegal to possess. At question is whether the accused had knowledge that he possessed the file. But that is a question for the trial, not for investigators. Once they knew there was one or more illegal files on the hard drive that is sufficient to justify a search without a warrant of that drive.
The defense attorney,
It is important to understand exactly how the law views searches under the 4th Amendment;
https://www.justice.gov/sites/default/files/criminal-ccips/legacy/2015/01/14/ssmanual2009.pdf
By this document, the definition of a search is; "a “‘search’ occurs when an expectation of privacy that society is prepared to consider reasonable is infringed.” furthermore, "If the government’s conduct does not violate a person’s “reasonable expectation of privacy,” then formally it does not constitute a Fourth Amendment “search” and no warrant is required."
So in simplest terms, because the accused asked Geek Squad to recover the files on the computer, he no longer has a reasonable expectation of privacy regarding the files he asked them to recover. No warrant is required for the FBI to seize the drive or to search any of the files recovered by Geek Squad. Now the question becomes, what about the rest of the contents of the drive. At this point I am going to back off playing forum lawyer. It looks like to me that all the files that the Geek Squad recovered are open to the FBI to look at without it even being a search according to the law. The part that gets fuzzy is, what about the rest of the drive's data because to prove that the accused knew the data was there, they will need to forensically identify that the accused knew it was there.
https://www.justice.gov/sites/default/files/criminal-ccips/legacy/2015/01/14/ssmanual2009.pdf
The fact that he wanted his files recovered gives us a reason for why the guy found the file. I'm not a lawyer, but I'm not sure about that exception to the 4th in this case (and honestly I think it's pretty fucking dumb not to get a warrant...why risk it?). I'm guessing that other files were found. I don't know that, but getting the search tossed would get him off no matter how many files there are. OTOH, if it's just the one file, I think it's going to be harder to successfully argue that he intentionally downloaded kiddie porn.
I'm moving towards the Fed's side, but I ain't there yet.