I know exactly what you mean.  It is definitely a female voice  It goes "AAAAAAAA  AAh  AAh," and during the first grouping the tone drops three times, and then remains the same for the following two short-screams.  If you ever see a cheapo gadget that uses a scream sound (think hallowen) I bet you that's it.  I have also heard it on more than one occasion in tv, commercials, and even a movie or two.