Although the statute does not permit a relator to pursue a qui tam action where the fraud is public knowledge, where the relator uses privately available information to make sense of the public information and the public information, standing alone, would not reasonably or plausibly supported an inference of fraud under the heightened pleading requirements for the claim.
http://www2.ca3.uscourts.gov/opinarch/164418p.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.