A 58-year-old woman is discovered dead in her home in Bangalore. The body is in a state of advanced decomposition with skeletonization of the hands and feet, and the soft tissues are largely liquefied. The room temperature is estimated to have been 28–32°C. Entomological evidence (fly pupae and beetle remains) is present. The family reports she was last seen alive 6 months ago. What is the most appropriate next step in determining the post-mortem interval?