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 Kamwina Nsapu group spoke the Tshiluba language.
reason: Since the text stated that the police officers spoke this language, the agent may have picked up the name of the language and linked it to that being the language spoken, but it doesn't necessarily mean that the terrorist spoke this language. 