A mass grave of about 70 to 100 corpses, with the majority of them having their throats slit, was discovered near the Nigerian town of Damasak last week, and is believed to be the brutal handiwork of the Islamic State's newest affiliate group, Boko Haram.
According to a witness who spoke with Reuters, soldiers from Niger and Chad, who were responsible for initially driving Boko Haram out of the town, found the mass grave left under a concrete bridge.
The bridge is believed to have been an execution site for the militant group, which has killed over 10,000 people in the last year and has seized a sizeable area of Nigeria's northeastern Borno state.
The exact number of bodies left by the group has been debated and has not been verified. The AFP news agency reports that Soldiers from Chad, who found the bodies last week, said there were at least 100 bodies laying in and around the dried-up riverbed. However, the Reuters witness only counted 70.
"There are about 100 bodies spread around, under the bridge just outside of town," Chad military spokesman Colonel Azem Bermandoa Agouna told AFP. "This is the work of Boko Haram."
While many of the victims had their throats slit, Agouna said that some of the victims had been decapitated, while others were shot to death.
Agouna added that the bodies were found somewhat mummified by the dry desert air and stated that the killings likely occurred about two months ago. The Reuters report stated that grass had also started to grow around the bodies.
"There are heads here and bodies there," Agouna explained. "The mass grave has become like a termite mound."
Although Boko Haram took control of Damasak last November, the group was driven out of the town on March 9 after a collaborated attack by troops from neighboring Niger and Chad. Most of the people in Damasak fled the town as Boko Haram took control.
Even though the militants were driven out of the town, residents said Tuesday that Boko Haram fighters returned and kidnapped over 400 women and children and killed about 50 of them before leaving the town again, Reuters reported.
Since troops from Niger, Chad and Cameroon have started working together to battle Boko Haram, the militant group has continuously been on the retreat. At the start of 2015, Boko Haram controlled about 20 local government districts. Last week, Nigeria's military announced that Boko Haram had been driven out of all but three districts.
Last week, Boko Haram militants fled out of the town of Bama due to fear of a Nigerian military assault on the town. But before the militants left the town, they killed their own wives so that they could not remarry to non-believers.
Fanna Aisami, a 52-year-old who fled from Bama and is now staying in Maiduguri, told The Daily Mail that a top Boko Haram commander warned of the wives' executions.
"He informed them of the situation and the consequence of the takeover of the town by advancing troops," Aisami said. "He warned that when soldiers killed them they would take their wives back to the society where they would be forced to marry and live with infidels… [the commander] said it would be better for them to kill their wives and send them to heaven."