The Engine w/5 and the Wagon w/4 went to the 3rd due on the southeast side of the county for a residential fire around 1830 hrs. Additional information reported a male victim was still inside, Engine 4 arrived with a fully involved single story structure and Chief 41 in command. Wagon 1 arrived, made entry through the back door, and quickly located the victim. It was determined to be too late; the homeowner had passed due to his injuries. The cause of the fire is under investigation.