Four men are being investigated for allegedly installing a spy cam in a women's dressing room in 2016. gettyimagesbank

By Dong Sun-hwa

Four former high school classmates are being investigated for a crime they allegedly committed three years ago ― installing a spy cam in the women's dressing room of their school dormitory in Daegu, police said Tuesday.

They all have now graduated. One, a medical student, 22, is under police probe. The others, now serving compulsory military service, are under Army investigation.

The medical student allegedly put up the spy cam in 2016 when he was a high school senior, police said.

Thirteen victims have so far been confirmed. But the actual number could be higher, considering many more women had used the dressing room.

The incident belatedly surfaced after the victims' families reported the case to the Daegu Metropolitan Police Agency early this year. Videos of the women in a dressing room were circulated, prompting the call to authorities.

Police discovered some videos on the mobile phone of an alleged offender who is in the military. They are working on digital forensic analyses for more evidence.