A series on tv i cant remember the name to?

Hi a few years ago there was this tv series about aliens and in one of the first few episodes it showed them as a big like ball of light and they made a sound like knives hit eachother, and it either killed anyone who heard or started mutating them. There were thing where they wopuld find a cabbage patch with human qualities grouning with them like teeth and such. i think the girl who worked for the efbi or something was a red head. Does anyone know what show im talking about? Thanks