A Fond du Lac man was killed after he rear ended a semitruck that was slowing down for a traffic backup caused by another crash. It happened just before six Tuesday evening on Interstate 41, about three miles south of Oshkosh. Winnebago County sheriff’s deputies say the first crash happened when a woman hit a semi and veered into a farm field where her S-U-V overturned. That caused a backup which resulted in the second and fatal mishap about 25 minutes later. None of the victims’ names were immediately released.