GREENFIELD, Wis. (WFRV) - Authorities in central Wisconsin are revisiting the unsolved case of Robert Christian, who disappeared on September 16, 1977. Christian, a Madison resident, had planned to meet a friend for bow hunting near Baraboo. When he failed to arrive, his family began searching near his usual hunting grounds in the township of Greenfield, along Tower Road between Bluff Road and the Sauk/Columbia County line. Driver hospitalized after vehicle falls through ice on Shawano Lake Later, Christian's 1977 AMC Hornet was discovered abandoned at a radio tower site. The car’s wheels and battery were missing, the vehicle was unlocked, and most of his personal belongings and hunting gear were gone. A comprehensive search, including ground teams, bloodhounds, and an aerial unit from the Army National Guard, yielded no trace of Christian. About a week later, investigators followed a tip to a quarry near the Badger Army Ammunition Plant. There, they found four tires and hubcaps compatible with Christian’s AMC Hornet, though it remains unclear if these were linked to his disappearance or were taken after his car was abandoned. A witness later reported seeing a car matching Christian’s AMC Hornet at about 8:00 p.m. on the night of his disappearance near the Durward’s Glen Retreat Center. Green Lake County reports spike in sign vandalism, seeks public’s help The driver, a young man resembling Christian, told the witness he was looking for a friend and then drove away. His identity was never confirmed. The Sauk County Sheriff's Office continues to seek information that could shed light on this decades-old mystery. Anyone with information is encouraged to contact the Sauk County Sheriff's Office at 608-355-3210.