The Canadian media wants to feed the narrative of America being a horrible, dangerous, backwards place where visitors get killed who arrive from nice places like Australia or New Zealand or Sweden or Canada or whatever.

It is simply less bang for the buck, toward that narrative, if it is an American-born woman.

Unless the American-born woman is black and the cop is white, then that will fit under the wanted narrative of "America is a horrible, dangerous, backwards place full of racist cops who slaughter people of colour".