Re: @Voland ...You are missing the point
Except your simple solution assumes the FBI has no in-house expertise on digital storage forensics...
As to this, the FBI has been having a difficult time hiring and retaining people who do this exact sort of work. This has been well covered, both here on El Reg and in other media outlets. They seem to want to get people with the skill set needed to do this kind of work to do so at government worker wages instead of the much high amounts they can get working as contractors or in private industry.