Nigeria, Sept. 15 -- At about 2 pm on Friday, 21 August, Muslims gathered for Juma'at prayers at a mosque in Kpenya, a community in Dekara District of Borgu Local Government Area of Niger State. For the worshippers, it was an ordinary Friday afternoon. Until armed men stormed the community.

Within minutes, worshippers were being marched away towards the surrounding forests.

The attackers also raided nearby communities, including Gidan-Zana and Sabon-Gida. By the time they left, scores of people had reportedly been abducted and about 30 people were dead. Thousands more fled, some across the border into neighbouring Benin Republic.

Then came a disturbing complication. A video circulated showing what appeared to be hundreds of women, chil...