In response to an informant's tip, a deputy sheriff stopped a van-type truck occupied by two of D's alleged co-conspirators. The truck contained distillery apparatus and raw materials. A fire broke out in a warehouse rented to d. Firemen discovered a 7,500-gallon-capacity distillery, 175 gallons of non-tax-paid whiskey, and related paraphernalia. Two weeks later P presented grand jury subpoenas issued in blank by the clerk of the District Court, to the presidents of the Citizens & Southern National Bank of Warner Robins and the Bank of Byron, where D maintained accounts. The two presidents were required to produce 'all records of accounts, i.e., savings, checking, loan or otherwise, in the name of D.' The banks did not alert D that the subpoenas had been served but ordered their employees to make the records available and to provide copies of any documents the agents desired. About 3 weeks after the return date on the subpoenas, D and four others were indicted. The overt acts alleged to have been committed in furtherance of the conspiracy included three financial transactions - the rental by D of the van-type truck, the purchase by D of radio equipment, and the purchase by D of a quantity of sheet metal and metal pipe. The record does not indicate whether any of the bank records were in fact presented to the grand jury. They were used in the investigation and provided 'one or two' investigatory leads. Copies of the checks also were introduced at trial to establish the overt acts described above. D moved to suppress. The court refused. On appeal citing the prohibition in Boyd v. United States against 'compulsory production of a man's private papers to establish a criminal charge against him,' the court held that the Government had improperly circumvented Boyd's protections of respondent's Fourth Amendment right against 'unreasonable searches and seizures' by 'first requiring a third party bank to copy all of its depositors' personal checks and then, with an improper invocation of legal process, calling upon the bank to allow inspection and reproduction of those copies.' The court acknowledged that the recordkeeping requirements of the Bank Secrecy Act had been held to be constitutional on their face but that access to the records was to be controlled by 'existing legal process.' It reversed and P appealed. P contends that the Court of Appeals erred in three respects: (i) in finding that D had the Fourth Amendment interest necessary to entitle him to challenge the validity of the subpoenas duces tecum through his motion to suppress; (ii) in holding that the subpoenas were defective; and (iii) in determining that suppression of the evidence obtained was the appropriate remedy if a constitutional violation did take place.