EXHIBIT 16 ARTHUR ANDERSEN ----------------------------- Arthur Andersen LLP ----------------------------- 8000 Towers Crescent Drive Vienna VA 22182-2735 703-734-7300 August 28, 1998 Office of the Chief Accountant Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 Dear Sir/Madam: We have read the first three paragraphs of Item 4 included in the Form 8-K dated August 24, 1998, of Infodata Systems, Inc., to be filed with the Securities and Exchange Commission and are in agreement with the statements contained therein. Very truly yours, ARTHUR ANDERSEN LLP cc: Mr. Christopher Dettmar, CFO, Infodata Systems, Inc.