Complex sentence: The autopsy, performed by experienced pathologists, earned much criticism and came to the conclusion that the Grimes sisters died on December 28, the day they vanished, and that they died because of shock and exposure to low temperatures.
Split into simpler sentences: The autopsy, performed by experienced pathologists, earned much criticism. They concluded that the Grimes sisters died on December 28, the day they vanished, and the cause of death was due to shock and exposure to low temperatures.