Don't know the circumstances, but a friend of mine who was a WWII vet told me about working with the "Huks" while stationed in the Philippines. They would slither out of camp at night with a knife between their teeth and come back the next morning with "Japanese ears" as a testament to their evening's work. They would cut the throat of one man in the foxhole and take his ear. The next morning the rest of those in the foxhole would realize they could have been like him. It was devastating to their morale.
They did the same thing to Jap soldiers who were occupying the U S Army’s barracks at Fort Stotsenberg (Later Clark Air Base). Jap was terrified.