KRMG was the first media outlet to pull up at a scene in south Tulsa Thursday afternoon.
Police were called to the Walmart parking lot at 66th and Memorial around 2:30 when a body was found in an SUV.
Investigators checked surveillance video and believe the body may have been there since February.
Police told KRMG there was no obvious sign of trauma.
The medical examiner has the body and will try to determine a cause of death.
TPD said it appeared the man had been living inside the vehicle.