Prosecutors in Waushara County have filed negligent homicide charges against a 76-year-old driver who hit two girls at a school bus stop last February.  Six-year-old Maryana Kranz was killed and her four-year-old sister was injured.  Investigators say Carl Mullenix was apparently driving on the sidewalk in the Town of Oasis when he hit the girls.  Waushara County Sheriff Wally Zuehlke says the bus was stopped and its lights were flashing.  The girls’ mother has filed a wrongful death lawsuit against Mullenix and his insurance company.  A hearing in that suit is set for January 19th.