O.J. Simpson's defense team is using its legal muscle to find out why juicy snippets of information about their client end up nightly on America's TV screens. They're forcing a reporter for KNBC-TV, her boss, the Los Angeles police chief and the spokesman for the department to testify in court under subpoena. KNBC-TV, you recall, was the station that reported DNA tests linked blood on O.J.'s socks to that of Nicole Simpson. KNBC-TV reporter Tracie Savage later said her sources provided inaccurate information. Judge Lance Ito will take up the issue of leaks tomorrow.