Officials at Thomas Pyle Middle School, outside the nation's capital, confiscated a student's iPod Touch with photos and video of female students after he apparently rented it to fellow students so they could see the sexually explicit images, The Washington Post reported Saturday.
Investigators said they were trying to figure out how the boy, who has been identified, amassed a large collection of the photos, Montgomery County police Cpl. Daniel Friz said.
He said police were trying to determine if any crimes had been committed.
The students in the photos attend Pyle and nearby Whitman High School, both in Bethesda, Md.
The girls apparently posed willingly off school grounds, then text-messaged or e-mailed other students the images, which had been circulated at least several months, the Post said.
Apparently, no adults were involved.
Detectives were still trying to identify the girls and hope to interview them, Friz said.
The prevalence of "sexting" -- sending or receiving nude or nearly nude photos via text message – has alarmed some parents and school administrators.
About one in seven American teens with cell phones reports receiving such photos, the Pew Research Center's Internet & American Life Project has found. Only 4 percent of students admitted sending explicit images, usually sent to a boyfriend, girlfriend or crush, Pew said.
Most state child pornography laws are meant to keep adults from exploiting children, not to punish children for sexting if the image is not of a child younger than 18.