The only prehistoric human remains uncovered in the Rancho La Brea area were those of the La Brea Woman, found in 1914. Excavators uncovered a woman's skull and partial skeleton. She had died about 9,000 years ago and was believed to have been about 18-24 years old and stood about 4 feet, 8-10 inches (1.5 meters) tall. Wear on her surviving teeth indicated a diet of stone-ground meal. Her skull structure indicated that she was of the Chumash people. Her skull was also found fractured, suggesting a blow to the head that may have killed her. She might just be Los Angeles' first known homicide victim. A broken grinding stone was found nearby (a common burial item among Southern California aboriginal people) along with the remains of a domestic dog.
Source: The Page Museum at the La Brea Tar Pits (and thanks, Claire, for your notes!)