decompose
/ˌdiːkəmˈpəʊz ˌडीकम्ˈपोज़्/ verb [I, T] to slowly be destroyed by natural chemical processes प्राकृतिक रासायनिक प्रक्रियाओं द्वारा क्रमशः नष्ट हो जाना, विघटित होना
The body was so badly decomposed that it couldn’t be identified.