Help...Whistling Sound?
 

I purchased a demo Mazda3 last week and quickly discovered a whistling noise coming from the front windshield of the car.
I have tried sealing the window with painter's tape to determine if the problem was an air leak but the whistling did not go away...
Any advice on what the problem could be? The whistling starts at 60km and is quite loud (and distracting) at highway speeds. Low speeds=no sound.