Same thing, got call on a Seattle area code. Answered the call, heard a man say 'Hi' then all went silent. waited for a few moments and then ended the call.
Just got the call, answered, a guy said hello and call was lost. I have bad reception in my apartment so I have no idea if they disconnected or if it was my end. But still. I do know that when calling people, they are able to change the number that you will see on your caller id. So the call could really be coming from anywhere.