“ISIS is basically co-opting a group in Congo that has been carrying out atrocities against civilians for some time,” said Mr. Poole.
Among the data points that indicate a link to ISIS in eastern Congo is the claim that the recent attack was carried out under the banner of the “Central Africa Wilayat.” According to the Islamic State’s own literature, the religious empire it calls a caliphate is divided into 35 “wilayats” or provinces, 16 of which are outside Iraq and Syria.
While the recent attack is the first to be claimed for this newly minted province, it isn’t the first time the province has been mentioned.
In one of his rare audio recordings, released in 2018, the ISIS leader Abu Bakr al-Baghdadi made a passing reference to a Central African province, suggesting that the geographic subdivision had existed in the terror group’s own nomenclature as far back as last year.
One of the most tantalizing clues is the discovery of the hard-bound book published by the Islamic State department dedicated to articulating its ideology.
Congolese troops recovered it last year from the corpse of an A.D.F. combatant, said Mr. Poole. Another copy of the same book was discovered by a team of Times reporters in the Iraqi city of Mosul, in a building formerly occupied by the Islamic State’s suicide bomber squad.
First issued in late 2014, the book provides an overview of how the Islamic State is supposed to be run and acts as a primer for those trying to establish a new territory under the group’s aegis, said Cole Bunzel, a research fellow in Islamic law and civilization at Yale Law School.
“The physical aspect is super interesting,” said Caleb Weiss, a research analyst who wrote about the Islamic State’s expansion into Congo for the Foundation for Defense of Democracies’ Long War Journal. “We don’t know if they published the book themselves, or if it was brought there, in which case it had to move through several countries to get to the Democratic Republic of Congo.”