NBC News anchor Brian Williams, who apologized on the air Wednesday night for lying about an experience covering the Iraq War, is now facing scrutiny over his gripping accounts of Hurricane Katrina, the disaster that burnished his nightly news bona fides almost a decade ago. Williams’ account of seeing a body float by in the French Quarter — which remained largely dry — and even a claim of catching dysentery from drinking Katrina floodwaters have raised eyebrows among bloggers and elsewhere since he took it on the chin this week over a claim that he rode in a helicopter that...