Tragedy marred the start of day TWO of the Republican National Convention in Milwaukee. Police officers shot and killed a man witnesses say was acting in a threatening manner just outside the secure perimeter around Fiserve Arena just hours before Day Two activities were set to get underway. The man was shot while walking across a street near a homeless encampment where he lived. Witnesses say the man had at least two knives and had thrown one at the officers. An investigation is underway. Bob Agnew, reporting from the Republican National Convention in Milwaukee.