The arrest of two Yotsuya Otsuka cram school teachers in western Tokyo for allegedly taking photos of a female student's underwear and sharing them on a social media group chat has sparked debate about how to protect children from sexual misconduct.

According to investigators, Narumi Nakamura, 26, allegedly had a 7-year-old elementary school student stand on a chair when they were alone in the room for a lesson. Colleague Sosho Mori, 24, who had previously been arrested for taking inappropriate photos of other girls, took pictures with his smartphone from underneath the student's skirt, they said.

The Metropolitan Police Department also served a separate arrest warrant to Mori for accessing students' personal information in the Yotsuya Otsuka database and sharing names, addresses and where they go to school in the group chat, in violation of the personal information law.