This is a complicated fourth amendment case that was decided by the Supreme Court in 1960.
Elkins and Clark were suspected of distributing pornography. State Police, beleived that they had in their possession obscene motion pictures, and got a search warrant to search Clark's home. The warrant was based ‘upon information and belief’ that Clark possessed obscene pictures and accompanying sound recordings. The search revealed no obscene pictures, but various paraphernalia believed to have been used in making wiretaps were found and seized.
The County District Court in Oregon held the search warrant invalid and ordered suppression of the evidence. This happened AFTER the return of an indictment by a STATE grand jury, and the local district attorney challenged the power of the district court to suppress evidence once an indictment was in.
Accordingly, the question was argued anew and the state court held the search unlawful and granted the motion to suppress. The state indictment was subsequently dismissed.
During the course of the state proceedings FEDERAL officers, acting under a FEDERAL search warrant, obtained the articles from the safe-deposit box of a local bank where the state officials had placed them. Shortly after the STATE case was abandoned, a FEDERAL indictment was returned, and prosecution followed.
At the FEDERAL hearing the judge assumed that the articles had been obtained as the result of an unreasonable search and seizure, but denied the motion to suppress because there was no evidence that any ‘agent of the United States had any knowledge or information or suspicion of any kind that this search was being contemplated or was eventually made by the State officers until they read about it in the newspaper.’ At the trial the articles in question were admitted in evidence against the petitioners, and they were convicted. They appealed and the appeals court agreed with the Federal judge.
When it went to the Supreme Court, however, the Court vacated the decision of the Appeals Court and remanded it to them to try again.
From the Court's decision:
"...we hold that evidence obtained by state officers during a search which, if conducted by federal officers, would have violated the defendant's immunity from unreasonable searches and seizures under the Fourth Amendment is inadmissible over the defendant's timely objection in a federal criminal trial. In determining whether there has been an unreasonable search and seizure by state officers, a federal court must make an independent inquiry, whether or not there has been such an inquiry by a state court, and irrespective of how any such inquiry may have turned out. The test is one of federal law, neither enlarged by what one state court may have countenanced, nor diminished by what another may have colorably suppressed."
Elkins is often cited for its "silver platter doctrine," that holds that more stringent limitations apply to federal officers than on state police acting independent of them. Most quoted is the section that explains that the purpose of the exclusionary rule is “to deter -- to compel respect for the constitutional guaranty ... by removing the incentive to disregard it.”
Probably more than you wanted, but it is a complex case, and I wanted to make sure I gave you enough that you could use it however you needed to.