The attack was so traumatizing even officers responding to the scene were offered professional support.
Mohamad Rafi Udin and two others were said to have taken part in a June 2016 video showing Islamic State members executing a prisoner.
State CID chief says the video originated from South America and was falsely linked to the discovery of a woman's head in Sri Aman.
Some Facebook users have linked the clip to a murder in Sri Aman, but police say there is no connection as the video originated from South America.
Plantation workers and villagers are sometimes known to attack an animal that they see as a pest, while poachers also capture them to sell as pets.
Al Habsi Misaya is killed by Philippine's security forces in the jungles between the towns of Indanan and Parang in the Sulu province.
Muamar Askali alias Abu Rami is said to have died in a clash with Philippine security forces.
Militant group's spokesperson says Robert Hall's body will turn up somewhere in Jolo today.