Nov. 26 (UPI) -- The Federal Bureau of Investigation says the American public should be vigilant this holiday season with a reported uptick in scams that target shoppers and charitable donors. "Criminals don't take holidays off," said Special Agent in Charge Robert Tripp of the FBI's San Francisco field office on Monday in a release . Advertisement According to the FBI, criminals have been actively exploiting this busy shopping period by using "increasingly sophisticated" tactics in order to