Brookfield police are investigating an incident where some students at Brookfield East High School were trading pictures of nude female students.

According to an affidavit filed in Waukesha County Circuit Court Thursday, Brookfield police are investigating the trading of the images of underage female students at the school after the mother of one male student informed officers about the images. She said her son had been on an overnight trip for the soccer club when a friend showed him nude photos of a female student from the school.

The woman said there were other pictures being passed around and bragged that students were trading the pictures “like Pokemon cards.”

Officers seized the other boy’s phone and they were able to identify the girl in the photos. When she was asked about them, she began to cry and said she sent the photos to her boyfriend and they had been taken during the summer of 2011.

The incident remains under investigation.