The Rock County Sheriff’s Office is investigating a fatal two-vehicle crash in Fulton Township.  The sheriff’s office reports a 56-year-old Janesville man was killed in the crash near North Highway 51 and West Arrowhead Shores Road.  Deputies report the victim was driving a small vehicle northbound around 6:30 Saturday night and hit a southbound SUV.  He was ejected, and his passenger, a 54-year-old woman from Indianford was critically injured.  Three occupants in the SUV also suffered non-life threatening injures.