What law, if any, limits the use of "terror" intel for non-terror law-enforcement?

[cthulu2016]

Say you get a warrant to search a house for a meth lab and find no drug evidence there, but instead find that the homeowner has bodies stacked in the basement.

The warrant you got had nothing to do with a serial killer investigation. There was no probable cause to suspect the guy of killing anyone.

But the fellow will be arrested for murder, and the evidence turned up by that search will be admissible evidence.

If the government came by a datum legally then it is properly in the system and government can use that datum for other lawful purposes unless there is some law preventing them from doing so.

Is there a law preventing data collected under a FISA warrant from being used for investigations other than the investigation for which the original warrant was issued?

I recognize that the NSA has a policy of not sharing, but I do not know to what degree NSA data is legally segregated from other government activities.

Anyone know? Does everything the NSA does, thinks or imagines being classified serve effectively to keep it out of the system?

(This is not a rhetorical question implying there are no limits. I do not know what limitations exist in law, if any.)

[Th1onein]

1. I don't think that there is a law like that.

And if the search is "legal" then they can whatever they find, for whatever purposes they want.

We are now living in a police state.

[dkf]

4. They aren't revealing the illegal parts of their investigations.

This looks like a blatant misuse and an egregious violation of our rights. How is this not a high crime?

[Th1onein]

6. I know.

You can't "investigate" and violate someone's rights during the process and still have that evidence to use against them in court. It is fruit of the poison tree. The fact that you "recreate" the investigation doesn't matter. You wouldn't have known to investigate in the first place if you had not violated their rights.

[cthulu2016]

2. .

[dkf]

3. There are no limits. They are using it already and hiding it from us so we can't challenge it.

http://www.reuters.com/article/2013/08/05/us-dea-sod-idUSBRE97409R20130805

[1-Old-Man]

5. Please recall the propaganda that got us the Patriot Act - "Agencies had to share information"

Remember, its wasn't Bush's fault, it was all those Agencies who "stove-piped" (what the fuck is that supposed to mean) their information and wouldn't share it with others. That's why they couldn't 'connect the dots'. So the press shouted high and low, we must allow the Agencies to share information, no that's not enough, in fact we will require Agencies to share information. And we will arm local police forces as if they were going to be called up to fight foreign wars, and we have secret laws, secret police, secret courts and so many secret Agencies that absolutely no one can name them all or tell anybody how much we spend on them.