The FBI is investigating anonymous threats against the Goldman Sachs investment firm contained in handwritten letters warning that ``hundreds will die.'' Sent to newspapers across the country, the letters threaten the investment bank, warning, “We are inside. You cannot stop us.” The Star Ledger of Newark reported the letters were all mailed from Queens, and signed “A.Q., U.S.A.” One of the letters, postmarked June 27, was received recently by the newspaper. Goldman Sachs is based in New York, and has offices in London, Frankfurt, Tokyo, Hong Kong and other cities. About 3,000 people work in its 44-story Jersey City tower. ”We take all of these things seriously,” said New York FBI spokesman Bill Carter. Postal inspection authorities also are investigating. Company officials would not discuss the threat or their response to it. ”As a matter of policy, Goldman Sachs does not comment on internal security matters,” spokesman Michael DuVally told the newspaper.