U.S. Presses Inquiry Into Tech Concern
Federal criminal investigation into Computer Associates' accounting has intensified, with prosecutors in Brooklyn issuing grand jury subpoenas for testimony and documents from fromer employees and company's customers; use of grand jury signals that prosecutors have decided to devote significant time and effort to inquiry; prosecutors are examining whether top executives inflated company's sales and profits during last 1990's to reach $1.1 billion payday that was tied to performance of company's stock; are also looking into accounting change that company made in 2000 that effectively allowed company to coount some of its sales and profits twice; Computer Associates has said its accounting is proper; client Allstate Corp and former Computer Associates employee Mary Welch say they have received subpoenas to testify or provide documents to grand jury; photo (M)