On Thursday police began questioning Nguyen Tan Thanh, 47, and he is likely to face charges of "molesting children under 16."

On April 24, when Thanh dropped his son off at school, he inappropriately touched the cheeks and private parts of three students sitting in a classroom, Vietnam Plus reported.

They are seven years old, but their names have not been disclosed.

One of the victims told their mother about what happened. Truong, the mother, confronted the groper who apologized. She then complained to the police.

Preliminary investigation by the police found that Thanh had similarly abused three other students of the same age that day.

If found guilty, he faces imprisonment of six months to three years.

Official data on sexual harassment is not regularly published in Vietnam. But out of 1,600 reported cases of child abuse last year, 80 percent involved sexual assault, the Ministry of Public Security said at a conference last month.