The International Red Cross says Nigeria has the highest number of registered missing people due to conflict in the world. 22,000 are registered as missing in the country, but the true figure could be much higher.

Asibi's son is among those missing.

She tells the BBC that she can still remember the moment she left him behind while fleeing Boko Haram five years ago.

Her son's feet were numb because they had been hiding in a river all night and he couldn't travel any further.

Video producers: Naomi Scherbel-Ball, Mayeni Jones and Ayo Bello.