CHICAGO (CBS) — Police in Milwaukee have launched an investigation after three teenagers live streamed themselves having sex, while their classmates watched on their phones at school.

CBS 58 in Milwaukee reports two girls, 14 and 15, and a boy, 15, reportedly skipped school in January, and engaged in sex acts off school grounds, while streaming video live on Facebook. Four students watched the video on their phones while in health class at Barack Obama School of Career and Technical Education.

Authorities have issued a search warrant demanding Facebook hand over all the information it has on the 14-year-old girl’s account – including pictures, status history, videos, and user information such as name and IP address.

One mother said she was not pleased the school did not inform parents.

“I’m quite sure I’m not the only parent that doesn’t know about this,” she said.

Milwaukee Public Schools released a brief statement about the incident:

“In January, staff became aware of a video depicting inappropriate conduct that took place outside of school and off campus. The school immediately notified proper authorities and cooperated with the investigation. We took appropriate disciplinary action against those involved, which would be in addition to any outside consequences they may face.”

According to CBS 58, the warrant says the two girls in the video could be charged with “exposing a child to harmful material.” The boy in the video was not listed as a suspect on the warrant.