San Diego police say dozens of students could face criminal charges for sending sexually explicit photos of fellow students.

Police say it all started when a dozen teen girls took naked pictures of themselves and texted them to their boyfriends. Soon, those photos reached friends at six different high schools and a middle school in San Diego.

Some of the girls, according to police, were as young as 13 and many of them did not know their photos have been circulated.

"We have several hundred photographs to look through. We have a much smaller number of pictures that actually have a face shot that will provide us an opportunity to identify who it is," San Diego Police Lt. Chuck Haye said.

Some of the male students who received and forwarded the graphic images could be charged with possession or distribution of child pornography.

The San Dieguito Union High School District said in a statement to ABC News it is cooperating with the investigation and that it encouraged parents "…to consistently monitor teen-use of cellular phone and other technologies."

Parents in the area say they need to remind their children about the potential consequences they face when sending or posting nude photos.

"What I tell my kids all the time is you're really just one screen shot away from ruining your lives," said Gordon Cooke, whose 14-year-old daughter attends Canyon Crest Academy in San Diego.

Getty Images