Park Avenue. McCarthy assured DeVita that neither LaStrada nor Ferran had done any work at either the Graybar Building or 230 Park Avenue, and the documents themselves showed that the invoices for the "Electronic Security System" were actually for an outdoor music system at Dunellen Hall. On the basis of the information and documents provided by McCarthy, the Government served grand jury subpoenas on approximately twenty Helmsley employees in December 1986.
In early January, 1987, the Government's investigation took a substantial leap forward when Parcher, Arisohn & Hayes released a series of documents which included two memos from Helmsley employee Frank Turco, dated August 22, 1985 and January 17, 1986. These "Turco memos", Government Exhibits 18 and 21 at trial, were the most crucial pieces of Government evidence toevidence to substantiate its case.
In late December 1986, after DeVita learned that the New York State Attorney General was conducting a parallel investigation based on the December 2 Post article, the United States Attorney's office began discussions with the New York Attorney General's office to confront potential problems presented by their independent but overlapping investigations. Eventually, the two offices decided to conduct joint federal and state grand jury investigations, with members of each of the two prosecuting offices cross-designated to participate in both grand-jury investigations.
*936 Sometime prior to the actual cross-designations, which did not occur before late January 1987, DeVita learned that Mrs. Helmsley had testified under immunity before a state grand jury in an investigation conducted by the Attorney General's office, and in an investigation conducted by