At the time of the 9/11 attacks, San Francisco residents braced for tragedy

This is Ask an Expert where every weekday at 9:20am on KCBS we're giving you direct access to top experts in various fields. As we mark 25 years since the September 11th attacks, KCBS' Steve Scott spoke with KCBS Insider Phil Matier and Willie Brown, who was Mayor of San Francisco on 9/11.