The problem however is prosecutors and the police may sometimes go back and get the evidence they need again via "legal" means after first acquiring it unlawfully, without informing anyone how they first acquired the evidence.
It's common enough that there is a term for this tactic, but I can't remember it and my google-fu is weak this morning, apparently.
I too have forgotten the term for the tactic.
Police often use the Stingray Cell Phone tracking device without a warrant to catch criminals, and then hide that fact.
http://www.usatoday.com/story/news/2015/08/23/baltimore-police-stingray-cell-surveillance/31994181/
Defense attorneys assigned to many of those cases said they did not know a stingray had been used until USA TODAY contacted them, even though state law requires that they be told about electronic surveillance.
“I am astounded at the extent to which police have been so aggressively using this technology, how long they’ve been using it and the extent to which they have gone to create ruses to shield that use,” Stephen Mercer, the chief of forensics for Maryland’s public defenders, said.
Prosecutors said they, too, are sometimes left in the dark. "When our prosecutors are made aware that a detective used a cell-site stimulator, it is disclosed; however we rely upon the Police Department to provide us with that information," said Tammy Brown, a spokeswoman for the Baltimore's State's Attorney. "We are currently working with the Police Department to improve upon the process to better obtain this information in order to comply with the law.”
Stingrays are hardly the only way this occurs.
http://www.reuters.com/article/us-dea-sod-idUSBRE97409R20130805
A secretive U.S. Drug Enforcement Administration unit is funneling information from intelligence intercepts, wiretaps, informants and a massive database of telephone records to authorities across the nation to help them launch criminal investigations of Americans.
Although these cases rarely involve national security issues, documents reviewed by Reuters show that law enforcement agents have been directed to conceal how such investigations truly begin - not only from defense lawyers but also sometimes from prosecutors and judges.
The undated documents show that federal agents are trained to "recreate" the investigative trail to effectively cover up where the information originated, a practice that some experts say violates a defendant's Constitutional right to a fair trial. If defendants don't know how an investigation began, they cannot know to ask to review potential sources of exculpatory evidence - information that could reveal entrapment, mistakes or biased witnesses.
"I have never heard of anything like this at all," said Nancy Gertner, a Harvard Law School professor who served as a federal judge from 1994 to 2011. Gertner and other legal experts said the program sounds more troubling than recent disclosures that the National Security Agency has been collecting domestic phone records. The NSA effort is geared toward stopping terrorists; the DEA program targets common criminals, primarily drug dealers.
"It is one thing to create special rules for national security," Gertner said. "Ordinary crime is entirely different. It sounds like they are phonying up investigations."
The unit of the DEA that distributes the information is called the Special Operations Division, or SOD.
But what word best describes this technique/practice?
I know I've seen it somewhere, but I've forgotten it!

I should just call up the Special Operations Division of the DEA and ask them what word they are using for this in their office lingo.
Why not have a proper division of labor, and have a well oiled police state?
Have the feds break every single law to find criminals, then have them give "anonymous" tips to the local police about who the criminals are.
Then the police can perform normal investigations and get legal convictions much easier than currently because they start out "knowing" who's guilty.
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As for backdoors in Iphones, it's all fun and good until criminals figure out how to use the backdoor too.
Snowden on Wikileaks, how to hack anyone's IPhone, enjoy.
Maybe the Feds should be concentrating on the
WHOPPING $21 billion that will be stolen from the IRS this year through fraud.
AKA the state budget in
half the states in this country.