Burlington has long been known as the shining jewel in Vermont's crown, but a current of darkness flows beneath this charming port on Lake Champlain. There is a sordid side to the city that top-ten lists routinely call "one of the country's most livable cities," with stories of dirty cops, notorious ladies of the night, knife wielding psychopaths, lovers off the deep end and famous serial killers. Author and tour guide Thea Lewis...