Premise: The 2017 Congolese police decapitation attacks occurred on 23 March 2017 in the DR Congo. About 40 police officers were ambushed then decapitated. Six police officers were released. All of the surviving police spoke the Tshiluba language. The Kamwina Nsapu terrorist group attacked the police convoy.
Hypothesis: the Tshiluba language was spoken by all 4 police officers