It seems likely that the missing man, Randy Potter, committed suicide, and it likely happened the night he was reported missing, which according to KCTV 5, was Jan. 17. This is because, according to the Chicago Tribune, Potter's parking ticket was printed that day.
The fact that it took eight months to find Potter is astonishing. Although the Associated Press reports that Potter's body was covered by a blanket and the windows of the Ram were tinted, those aren't really excusable excuses. Potter's truck was in a large parking lot, one that holds nearly 6,000 cars, according to the Kansas City Star, but that shouldn't have mattered, since the company in charge of the lot, S-P+, was supposed to take an inventory of every car in the lot every single night. Plus, Potter's family took the license plate number of the truck to the parking lot security companies not long after his disappearance. Clearly no one from the parking company was watching closely.
As for the police, the Star reports that they never checked the airport since there wasn't any evidence to say he might have gone there. Yet they say they spent "several hundred man hours" on the case, and their operating theory was that he had left his family. One way people leave is by plane.
So how was the body finally discovered? Someone who parked nearby complained of a horrible smell. After eight months, no doubt. It's puzzling that no one would have reported a smell sooner. Though the problem would have been bad enough in winter and spring, it would have become pretty intense in the summer months, with high temperatures in the 90s translating into incredible heat inside a truck on shadeless pavement under the relentless Missouri sun.