One of the Chibok girls freed in May has been telling journalist Adaobi Tricia Nwaubani how a diary was kept of some of her three years in captivity with Boko Haram Islamist militants.

One of the oldest in her class, Naomi Adamu was 24 when she and more than 200 mainly Christian students were taken off into Boko Haram's Sambisa forest hideout in north-eastern Nigeria in 2014, sparking global outrage.

While in captivity, the girls were given exercise books for the Koranic classes they were made to attend.

But some of the girls used these to keep secret diaries. When the militants found out, they were forced to burn the books.

Ms Adamu managed to hide hers. She and her close friend, Sarah Samuel, now 20, and three other girls used the books to chronicle some of their experiences.