According to investigators, on Wednesday Logan left his home and got into the car with the family dog and quickly suffered heat stroke. The 9-year-old dog also died due to the heat.
"I know it was an accident," Logan's grandfather, Jimmy Clevinger, told local reporters. "My daughter was laying on the couch with him watching TV and my wife was in the bedroom."
Clevinger said the entire incident occurred in a matter of minutes and that his daughter quickly noticed Logan was missing.
"Anywhere from 15, 15 to 20 minutes, if that," Clevinger said of the time frame.
An ambulance was immediately called and Logan was taken to Carolinas Medical Center in Charlotte. He was pronounced dead shortly before 4 p.m. Sunday afternoon.
Logan Cox's death was tragically unexpected, as his parents were planning for his return sometime Monday.
Local police and the Department of Social Services are investigating to determine if charges will be filed. Logan's parents have said they are not ready to speak to the media yet and are currently planning Logan's funeral.
Notable deaths of 2014 [PHOTOS]