Clewley was last known to be in his remote summer cabin by the Tahquamenon River at Tahquamenon Falls State Park in the Upper Peninsula area of Michigan on July 12, 2008. His wife visited him at the cabin on July 10. She didn't like living there and would visit occasionally, while he stayed there alone for weeks at a time. He enjoyed hiking and was very familiar with the area. He and his wife spent winters in Florida. On July 13, Clewley missed his 9:00 a.m. and 9:00 p.m. check-in times with his wife. After he missed them again the next day, she and other family members asked the police to check on his welfare.

When officers arrived at the cabin, they found it locked and Clewley gone. There were no indications of foul play. His dog, a Chow/Springer Spaniel mix named Chip, disappeared with him. A photo of Chip is posted below this case summary. Clewley frequently took the dog with him when he went hiking. His 1992 Oldsmobile Silhouette van was found at the head of North Country Trail on the western side of the Tahwuamenon Falls State Park. Its gas tank was almost empty and it was unlocked with the keys left inside, something uncharacteristic of Clewley's behavior. A photo of the van is posted below this case summary. Twenty days after Clewley disappeared, Chip appeared at the cabin. The animal was thin but clean and in good condition, without bug bites or ticks, leading to speculation that someone had cared for it for at least part of the time after Clewley's disappearance.

Clewley was born and raised in Lansing, Michigan. He studied electrical design at Lansing Community College and went on to found Industrial Control Resources, an engineering services company. He also served with the Navy in Guam in the 1950s. Clewley has five children. His disappearance remains unsolved.

Left: Chip the dog;
Right: Clewley's van