The Dallas Police Department said Elizabeth Lightfoot was alive when someone set fire to her car late last week.
"To clarify the cause of death of Miss Lightfoot, she died from carbon monoxide poisoning due to the fire that was intentionally set by the suspect," said Kevin Janse, with the Dallas Police Department.
The 22-year-old woman's body was found in the driver's seat of her car after firefighters put out the car fire at about 2:30 a.m. Friday morning.
Lightfoot, a hairstylist at Salon Republic, had been out with friends at a restaurant earlier in the evening. At about midnight, they all left to go home.
All but Lightfoot made it home safely.
Lightfoot's death is being investigated as a homicide.
Anyone with information in the case is asked to call the Dallas Police Department Homicide Unit at 214-671-3661.