After over 1,095 days in captivity, you would expect the abducted Chibok school girls to crave for freedom. But the reverse seems to be the case.

Some of the girls are not willing to return. Their position was revealed by one of the negotiators involved in the release of the 82 Chibok girls on Saturday.

The militants on Saturday released some of the girls they kidnapped in April 2014 in exchange for prisoners in a swap deal.

A mediator and lawyer Zannah Mustapha said some of the abducted girls had refused to go home, fueling fears that they have been radicalised by the jihadists.

They are speculations that they may feel afraid, ashamed or too powerful to return to their old lives.

"Some girls refused to return ... I have never talked to one of the girls about their reasons," said 57-year-old Mustapha, who acted as an intermediary in the latest negotiations between the Nigerian government and Boko Haram.

"As a mediator, it is not part of my mandate to force them (to return home)," he told the Thomson Reuters Foundation in the capital Abuja.

The return of the 82 girls on Saturday marked the second group release of the Chibok girls by Boko Haram - with both deals brokered by Switzerland and the International Committee of the Red Cross - after 21 young women were released in October.

A few others have escaped or been rescued, and 113 of the girls are believed to be still held in captivity by Boko Haram.