You are conducting an autopsy of a body. Which of the following is the first internal sign of putrefaction that you are likely to observe?

Greenish discolouration of the right iliac fossa is the first external sign of putrefaction. It appears in about 12 - 24 hours. Marbling is most prominent after 31 - 48 hours, it is visible externally. The greenish discoloration of the under surface of the liver is the first internal sign of the putrefaction. Ref: Textbook of Forensic Medicine and Toxicology by Narayan Reddy, Edition 23, Page - 135, 136.