great time. you are going to be at the most well secured event in the city. >> reporter: already this weekend, officers in fayetteville north carolina arresting a man walking through the mall with an ar-15, vest and ammunition. clearly, this is going to be a busy weekend for law enforcement. >> it is. thanks for that. as you saw, one side of the security jitters was the response we witnessed at washington's navy yard. reports of shooting there turned out to be a false alarm. what happened? we are live in washington with more. >> good morning. that response was huge and quick showing just how on edge authorities are, treating every concern seriously, going into this holiday weekend. it all started yesterday morning at the navy yard. a woman inside called 911. she thought she heard a gunshot. within minutes, the building was on lockdown the streets shut