What follows is an opinion from the Supreme Court of the United States. Your task is to determine the bases on which the Supreme Court rested its decision with regard to the legal provision that the Court considered in the case. Consider "judicial review (national level)" if the majority determined the constitutionality of some action taken by some unit or official of the federal government, including an interstate compact. Consider "judicial review (state level)" if the majority determined the constitutionality of some action taken by some unit or official of a state or local government. Consider "statutory construction" for cases where the majority interpret a federal statute, treaty, or court rule; if the Court interprets a federal statute governing the powers or jurisdiction of a federal court; if the Court construes a state law as incompatible with a federal law; or if an administrative official interprets a federal statute. Do not consider "statutory construction" where an administrative agency or official acts "pursuant to" a statute, unless the Court interprets the statute to determine if administrative action is proper. Consider "interpretation of administrative regulation or rule, or executive order" if the majority treats federal administrative action in arriving at its decision.Consider "diversity jurisdiction" if the majority said in approximately so many words that under its diversity jurisdiction it is interpreting state law. Consider "federal common law" if the majority indicate that it used a judge-made "doctrine" or "rule; if the Court without more merely specifies the disposition the Court has made of the case and cites one or more of its own previously decided cases unless the citation is qualified by the word "see."; if the case concerns admiralty or maritime law, or some other aspect of the law of nations other than a treaty; if the case concerns the retroactive application of a constitutional provision or a previous decision of the Court; if the case concerns an exclusionary rule, the harmless error rule (though not the statute), the abstention doctrine, comity, res judicata, or collateral estoppel; or if the case concerns a "rule" or "doctrine" that is not specified as related to or connected with a constitutional or statutory provision. Consider "Supreme Court supervision of lower federal or state courts or original jurisdiction" otherwise (i.e., the residual code); for issues pertaining to non-statutorily based Judicial Power topics; for cases arising under the Court's original jurisdiction; in cases in which the Court denied or dismissed the petition for review or where the decision of a lower court is affirmed by a tie vote; or in workers' compensation litigation involving statutory interpretation and, in addition, a discussion of jury determination and/or the sufficiency of the evidence.

Opinion:
LUSTIG v. UNITED STATES.
No. 1389,
Oct. Term, 1946.
Argued April 19, 1948. — Reargued October 19, 1948.
Decided June 27, 1949.
Edward Halle argued the cause and filed the briefs for petitioner.
Solicitor General Perlman argued the cause for the United States. With him on the brief on the original argument were Assistant Attorney General Quinn, Robert S. Erdahl, Irving S. Shapiro and Philip R. Monahan. With him on the brief on the reargument were Assistant Attorney General Campbell, Mr. Erdahl and Josephine H. Klein.
Mr. Justice Frankfurter
announced the judgment of the Court and an opinion in which
Mr. Justice Douglas, Mr. Justice Murphy and Mr. Justice Rutledge join.
This is a prosecution under the counterfeiting statutes. Rev. Stat. § 5430, 35 Stat. 1088, 1116, 18 U. S. C. (1946 ed.) § 264 (now § 474). The sole question before us is the correctness of the denial of a pretrial motion, sustained by the Court of Appeals for the Third Circuit, 159 F. 2d 798, to suppress evidence claimed to have been seized in contravention of the Fourth Amendment as it is to be applied under the doctrine of Byars v. United States, 273 U. S. 28.
Since the legal issue turns on the precise circumstances of this case they must be stated with particularity.
At about 2 p. m. on Sunday, March 10, 1946, Secret Service Agent Greene received two telephone calls, one from the police of Camden, New Jersey, the other from the manager of a hotel in that city, indicating violations of the counterfeiting statutes being carried on in Room 402 of the hotel. Lustig, the petitioner here, and one Reynolds were registered for this room under assumed names. It is to be noted that the Secret Service is the agency of the Government charged with enforcement of the laws pertaining to counterfeiting. On looking through the keyhole of the suspect room after reaching the hotel, Greene saw Lustig, two brief cases and a large suitcase, but no evidence pertinent to counterfeiting. He questioned the chambermaid whose suspicions had led to this investigation. She recounted the hearing of noises “like glass hitting against glass or metal hitting against metal” emanating from the suspect room. She also remarked that she had seen what looked like money on the table.
Greene thereupon reported to Detective Arthur of the Camden police at the Camden Police Station that he had seen no evidence of counterfeiting but was confident that “something was going on.” Arthur reported the affair by telephone to his superior, Captain Koerner, at his home, who then came to the police station. In his account of the affair, Greene gave to Koerner the names under which the occupants of the room had registered. In reply to inquiry by Captain Koerner, Sergeant Murphy of the Camden police stated that one of the names was that of a “racehorse man or a tout or a bookie.” After verifying the names on the hotel register and on the assumption that the occupants of the room “might be trying to counterfeit race-track tickets” rather than currency, Koerner secured warrants for the arrest of persons bearing the names on the register in order to “get into that room and find out what was in there.” The offense charged against those bearing the assumed names was the violation of a Camden ordinance requiring “known criminals” to register with the local police within twenty-four hours after their arrival in town. At about four o’clock in the afternoon of the same day, Koerner and three city detectives secured a key from the manager of the hotel and entered Room 402. The police officers proceeded to empty the bags and the drawers of a bureau and thus came upon the evidence sought to be suppressed. What they found indicated counterfeiting of currency rather than of racetrack tickets.
During all this time, Greene had remained at police headquarters because he “was curious to see what they would find.” On finding what they did find, Koerner sent word to Greene, who came to the hotel and examined the evidence in controversy. When Lustig and Reynolds eventually returned they were arrested and searched by the detectives. As various articles were taken out of their pockets, those deemed to have bearing on counterfeiting currency were turned over to Greene. He observed that the ink on a $100 bill taken from Reynolds had not been tampered with. Greene was trying to discover what had been used to make the impression on the “similitude” found in the room. After the search was completed, Greene and the city police gathered up the articles revealed by the search and carried them to the police station. Some of' these articles were given to Greene before he left Room 402; all were eventually turned over to him.
We are confronted by a ruling of the District Court, sustained by the Court of Appeals, admitting the evidence. But the question before us is not foreclosed by the respect to be accorded to a ruling on an issue of fact by the trial court until analysis discloses that the ruling was merely on an issue of fact and that no issue of law was entwined in the ruling. Insofar as what the lower courts found as facts may properly be so regarded, they are to be accepted; but their constitutional significance is another matter.
On the basis of what was before him, the trial judge admitted the evidence because he did not “see any connivance or arrangement on the part of the Federal officers to have an illegal search made to get evidence they could not secure under the Federal law.” We therefore accept as a fact that Greene did not request the search, that, beyond indicating to the local police that there was something wrong, he was not the moving force of the search, and that the search was not undertaken by the police to help enforcement of a federal law. But search is a functional, not merely a physical, process. Search is not completed until effective appropriation, as part of an uninterrupted transaction, is made of illicitly obtained objects for subsequent proof of an offense. Greene’s selection of the evidence deemed important for use in a federal prosecution for counterfeiting, as part of the entire transaction in Room 402, was not severable, and therefore was part of the search carried on in that room. The uncontroverted facts show that before the search was concluded Greene was called in, and although he himself did not help to empty the physical containers of the seized articles he did share in the critical examination of the uncovered articles as the physical search proceeded. It surely can make no difference whether a state officer turns up the evidence and hands it over to a federal agent for his critical inspection with the view to its use in a federal prosecution, or the federal agent himself takes the articles out of a bag. It would trivialize law to base legal significance on such a differentiation. Had Greene accompanied the city police to the hotel, his participation could not be open to question even though the door of Room 402 had not been opened by him. See Johnson v. United States, 333 U. S. 10. To differentiate between participation from the beginning of an illegal search and joining it before it had run its course, would be to draw too fine a line in the application of the prohibition of the Fourth Amendment as interpreted in Byars v. United States, supra, 273 U. S. 28.
The crux of that doctrine is that a search is a search by a federal official if he had a hand in it; it is not a search by a federal official if evidence secured by state authorities is turned over to the federal authorities on a silver platter. The decisive factor in determining the applicability of the Byars case is the actuality of a share by a federal official in the total enterprise of securing and selecting evidence by other than sanctioned means. It is immaterial whether a federal agent originated the idea or joined in it while the search was in progress. So long as he was in it before the object of the search was completely accomplished, he must be deemed to have participated in it. Where there is participation on the part of federal officers it is not necessary to consider what would be the result if the search had been conducted entirely by State officers. Evidence secured through such federal participation is inadmissible for the same considerations as those which made Weeks v. United States, 232 U. S. 383, the governing principle in federal prosecutions.
Though state officers preceded Greene in illegally rummaging through the bags and bureau drawers in Room 402, they concerned themselves especially with turning up evidence of violations of the federal counterfeiting laws after Greene joined them. He was an expert in counterfeiting matters and had a vital share in sifting the evidence as the search proceeded. He exercised an expert's discretion in selecting or rejecting evidence that bore on counterfeiting. The fact that state officers preceded him in breach of the rights of privacy does not negative the legal significance of this collaboration in the illegal enterprise before it had run its course. Greene himself acknowledged such participation by his remark about "leaving the room after we had gathered all this evidence together.”
Nor is the search here defensible as incidental to a lawful arrest. Greene never made the arrest, he knew that Lustig and Reynolds were not present when he entered their room and he had an active hand in the continuation of the search without warrant before Lustig and Reynolds had returned. The ruling in Davis v. United States, 328 U. S. 582, does not come into play. Neither is it material that Greene may have been informed as to what he was likely to find before he joined the searchers. Vindicated anticipation of what an illegal search may reveal does not validate a search otherwise illegal. Trupiano v. United States, 334 U. S. 699, 708-9. With every respect for the rulings of the lower court, we find that the unquestioned facts disclose that the evidence on which the conviction rests was illicit and the motion to suppress it should have been granted.
Reversed.
Mr. Justice Black concurs in the judgment of the Court substantially for reasons set out in his dissent in Feldman v. United States, 322 U. S. 487, 494.
After this Court denied a petition for writ of certiorari, a petition for rehearing was granted. The order entered June 16, 1947, 331 U. S. 853, denying certiorari was vacated and the petition for writ of certiorari to the Court of Appeals for the Third Circuit was granted on February 16, 1948. 333 U. S. 835.

Question: What is the basis of the Supreme Court's decision?

Choices:
judicial review (national level)
judicial review (state level)
Supreme Court supervision of lower federal or state courts or original jurisdiction
statutory construction
interpretation of administrative regulation or rule, or executive order
diversity jurisdiction
federal common law

Answer: 6