> I don’t think that’s true. There’s a legal idea of “fruit of the poisonous tree”[0] that basically says you can’t use bad evidence, either in court or as an excuse to collect more, valid evidence.
I think the police have been using "parallel construction" to get around that for some time.
> Parallel construction is a law enforcement process of building a parallel, or separate, evidentiary basis for a criminal investigation in order to conceal how an investigation actually began.[1]
> In the US, a particular form is evidence laundering, where one police officer obtains evidence via means that are in violation of the Fourth Amendment's protection against unreasonable searches and seizures, and then passes it on to another officer, who builds on it and gets it accepted by the court under the good-faith exception as applied to the second officer.[2] This practice gained support after the Supreme Court's 2009 Herring v. United States decision.
While I'm sure it happens, I don't think that "evidence laundering" is particularly common, especially at the federal level. Cases I ran required an "initial notification" that succinctly described how our agents were notified of the potential criminal activity. The fear of having a case thrown out, or being turned down months into a high-level investigation because an attorney is uncomfortable with the likely outcome, is huge in ensuring a valid investigation is run.
Now, that's not to say that cops wouldn't do this in order to finally get a case around a particular subject who was able to sidestep previous investigations or something. I just doubt that it happens often enough to be worthwhile.
I think the police have been using "parallel construction" to get around that for some time.
https://en.wikipedia.org/wiki/Parallel_construction
> Parallel construction is a law enforcement process of building a parallel, or separate, evidentiary basis for a criminal investigation in order to conceal how an investigation actually began.[1]
> In the US, a particular form is evidence laundering, where one police officer obtains evidence via means that are in violation of the Fourth Amendment's protection against unreasonable searches and seizures, and then passes it on to another officer, who builds on it and gets it accepted by the court under the good-faith exception as applied to the second officer.[2] This practice gained support after the Supreme Court's 2009 Herring v. United States decision.