[liberationtech] Query on implications of dragnet eavesdropping

[Louis Suárez-Potts]

Hi,
This may be a banal or mundane query and probably doesn't directly pertain to recent reports of NSA tapping or any other agency's. But let's say that in their apparent dragnet the NSA or any other similar agency finds probable cause to consider one or more persons as involved in a conspiracy to commit a nonpolitical and very mundane but no less horrible crime; or say that they (the agency) comes to learn or strongly suspect that the subjects of interest have already done something criminal and awful.  

Would the agency be required to handover that incriminating information to the relevant local or federal police authority? Would they need a special warrant for doing that? Would even breaching the way in which this information was acquired be legally possible? (And thus, out of a sotto voce transmission, unlikely.)

And let's further suppose that the agency has captured what seems to be strong evidence that a crime will be committed but because of the circumstances of the data capture, the identity of the agency, and because it doesn't seem to relate to the ostensible purpose of the agency program, nothing is done (except an archive is made, presumably), and the criminal act is committed or the criminals who were recorded discussing it go on as before, unimpeded and free, at least for this particular act.

And if this failure of action by the agency, to notify relevant authorities and either prevent the act or arrest its committers, is then discovered by, say, upset family members, would they be able to sue the agency for a failure to act? (I"m thinking of people specifically harmed by the commission of the crime.)

Put another way, supposing that a record of what seems to be all communications taking place in a given nation is being assembled by an agency whose purpose is to protect the residents of a nation, where does one draw the line of government responsibility?

I'd guess that this question has actually been answered a long time ago, and I'd be delighted to learn of the references to prior discussions of the issues. It's an interesting point, at least to me, and also clarifies the logic of directed intelligence gathering predicted by a specific suspicion: namely, that the epistemological frame is tightly drawn (or ought to be), and thus the boundaries of responsibility to act are equally limited.

Cheers,
Louis