The area’s police boss Jonathan Ngala said Mohammed Alfayo was in police custody and was helping them with investigations.
He, however, said police were still looking for the girl “to establish whether the act was truly committed”.
“We have already commenced investigations. We will notify the public once we get to the bottom of the matter,” he went on.
Alfayo posted a picture of himself with an underage girl at a bush on Monday bragging about having sex with her in the bushes.
One of the pictures shows the poor girl lifting her top for the sick man to take a picture.