Updated 03/17/15 – 11:25 a.m.

CHICAGO (CBS) — Four teenagers could face criminal charges in a sexting scandal at a high school in northwest suburban Norridge.

Police said students at Ridgewood High School distributed explicit photos of underage classmates outside of school, using an app on their cell phones.

Two female students could face charges for taking nude photos of themselves, and two boys could face similar charges for sending those photos to other students. Police said the students used Snapchat to exchange explicit photos.

Norridge police began investigating last month, after a classmate heard about the pictures, and notified school officials.

Police said a 15-year-old girl first sent out photos of herself, then found out a 17-year-old girl also allegedly was taking nude selfies.

Two boys, ages 15 and 17, got caught distributing those photos to other classmates, according to police.

Authorities said several students saw the pictures.

Ridgewood Community High School District 234 would not say if those students have faced or would face any school-related disciplinary actions.

No email or letter went out to parents, but word spread quickly.

“This social media stuff is going to tank this whole generation if somebody doesn’t do something about this. It’s just crazy,” Ridgewood grandparent Bill Papish said. “I see what’s going on with these younger kids, and yeah, I think I can believe it. They’re just out of control. There’s nobody stopping them.”

Agnes Gubas said there should be minimum age limits for using social media.

“I know my daughter, and I know she wouldn’t do anything like that. She’s a good student, and she has good morals,” Gubas said.

Police said this was the first case of sexting at the high school, and many of the kids didn’t realize it is a crime to send explicit photos of youths that age.

Prosecutors were expected to make a decision on charges later this week.

The four students would be charged as juveniles, if prosecutors approve charges. The school district said it was letting police handle the matter.