D owned and operated a wholesale company that sells cooking oils to restaurants and retailers. IRS Special Agent Kevin Caramucci and six other agents went to D's offices and presented themselves at a locked iron security gate at the entrance, rang the bell, showed badges, and identified themselves. All of the agents wore business attire and carried concealed weapons. D unlocked the gate and allowed the agents to enter. Caramucci read D the so-called 'IRS Non-Custodial Statement of Rights Card.' D responded that he understood his rights and voluntarily agreed to answer questions. D cooperated and the Agents left after they received the documents they needed. D was charged in an information and brought to trial. P claimed that D failed to fully report income derived from sales to six of his customers. Representatives of five of the customers testified at trial concerning how they conducted business with D. P was unable to procure the testimony from the Wo Lee Co. P sought to introduce into evidence documents obtained from Wo Lee without calling anyone from Wo Lee to authenticate them. These consisted of original invoices issued by D and corresponding original canceled checks written on Wo Lee's bank account. Agent Caramucci testified that Wo Lee's owner gave these documents to IRS Agent Charlie Busch, who in turn gave them to Caramucci. D objected on hearsay and foundation grounds. D did not dispute, that the invoices are identical to numerous other invoices that were already admitted into evidence. Many of the invoices matched the carbonless copies of the same invoices contained in D's own records seized pursuant to a search warrant. Other invoices not matched with carbonless copies bore invoice numbers appearing in sequence with other invoices contained in D's invoice book. They were admitted and D was convicted and appealed.