The 24-year-old woman, who has not been publicly named by authorities, was taken into custody Wednesday after police analyzed the video and traced her to a specific neighborhood. She was later found there with the boy, whom she identified as her relative, Lagos state police spokesman Bala Elkana said.
The footage, which has sparked social media outrage in Nigeria, shows the woman flogging a half-dressed boy with a belt and then dragging him into a cage, which she locks.
Two dogs were inside kennels beside the cage where the boy was kept.
“She actually confessed that she was the one in the video and that he is a cousin who came to live with her after he lost his parents,” Elkana told CNN.
CNN has not been able to reach the woman to determine if she has a lawyer.
Police said the incident took place August 3 and that the woman claimed the boy provoked her after he became drunk and damaged her car.
“She told us that she got angry after the boy took some dry gin and broke the side mirror of her car. Then she locked him in the dog house for some hours. For this we are going to push to charge her with child abuse,” Elkana told CNN.
The suspect will remain in custody until she is taken to court Friday, police said, adding that the boy has been handed over to a government shelter in the city.