The following story is taken from "Bones: a forensic detective's casebook", by Dr. Douglas Ubelaker and Henry Scammell.
The victim failed to show up for work one morning, and he was reported missing by his employer. 18 days later, two dirt bikers driving through a rural area just a few miles away came across a burned-out car, and inside, slumped across the back seat, they saw the charred body. The police arrived, and a call went out for the forensic team on Knoxville, Tennessee. Bill Bass and his crew surveyed the crime scene, removed the corpse from the car, and when they returned to the laboratory they performed an autopsy on the blackened cadaver.
Live maggots were observed throughout the surface of the body. But when they removed the top of the skull, cooked maggots were found inside the brain. This was a significant discovery. It meant that the victim had been dead long enough for flies to leave larvae, for maggots to grow and eat away much of the decaying outer tissue and enter the braincase. By comparing the length and weight of the maggots inside the brain with his own charts of maggot development, Bill Bass concluded that the maggots had died between 14 and 16 days after the victim himself was killed. The maggots outside the body was determined to be approximately 2 days old. Bill Bass and his colleagues also found knife marks in the vertebrae.
Based on this evidence, very much of what had happened could be reconstructed. The man had been murdered with one or more knife stab and left in the back seat. Some two weeks later the people who did it came back and set fire to the car, maybe in the hope of getting rid of the corpse, or creating the impression he had died in an automobile accident. The fire went out, and the body cooled enough for the flies to come back and lay more eggs on the burnt material.