It started out as a joke.
A bunch of Oregon high school seniors posed for pictures at a local playground, wearing their Seaside High School cheerleader uniforms.
Then, some of the girls began revealing what they were wearing — and what they were not wearing — underneath.
"They were in their cheerleading outfits, lifting them up in front of the camera," said Seaside student Jessica Hauge. "Some of them, they had no shirts on."
Bawdy Fun, or Kiddie Porn Felony?
"The girls that took it, they thought it was funny," said former student Natalie Goodman. "They took it for the school since they were seniors ... and they thought it would be something fun to do."
School officials don't think it's very funny — and some of the girls may not be allowed to graduate this year. Police were not amused when the photos began appearing on the Internet, and say someone could be charged with a felony: the distribution of child porn.
Some of the images, officials say, were very explicit.
It is believed that a male student, a sophomore, used a digital camera to take the pictures. Somehow — and this is where the police are very interested in finding out what happened — those digital photos made it onto the Internet.
Investigators warned that anyone who distributes the photos is committing a felony in Oregon.
Police: This Is a Big Deal
"Some people may not think that it was a big deal, but it is a big deal," said Oregon State Police Lt. Gregg Hastings. Hastings said distributing sexually explicit photos of children in person or online is a crime.
"That's where you start approaching a felony here in our state," he said.
Seaside High School officials refused to discuss the case, but the girls in question are believed to be still attending school.
But some of their classmates hope they will be punished.
‘Wrong and Gross and Stupid’
"It's just going back to our school and making us look bad, and making us kids look slutty and stuff," said Seaside junior Crystal Cleveland.
"What they did was wrong, and gross and stupid," agreed former student Matt Castrape.
Police have questioned several people — adults and minors — but no arrests have been made.
ABCNEWS affiliate KATU in Portland, Ore., contributed to this report.