Police on Tuesday afternoon arrested a woman accused of sewing up her 10-year-old child's mouth because he attained poor grades.
Her arrest came hours after the incident was highlighted in the media.
Naivasha Deputy County Commissioner Mbogo Mathioya said police took the woman for questioning.
"She was arrested after turning up at the Naivasha based children's office to where she had been summoned," said the administrator.
A source at the department said the mother admitted piercing her son, a Class Five pupil, twice in the mouth in a "fit of anger."
She claimed the boy's disciplinary issues were laid bare when she visited the school on an academic day.
"The mother was enraged by her son's poor grades and disobedience claims by the teachers," the source said, adding that her payment of high school fees made matters worse.
The school administration brought the matter to the fore out of concern about the boy's visible injuries.
It was said that the boy would be taken to Naivasha Sub-county Hospital for a check-up.
"He will then be taken to a children's home where he will be housed as police investigate the matter," said Mr Mathioya.
The assault left Maai Mahiu residents in shock, with discussions taking place on social media platforms.
Naivasha Assistant County Commissioner Julius Nyaga warned parents against assaulting their children, saying stern action will be taken against them.
The Maai Mahiu-based administrator asked them to instead seek professional counselling.