The Baltimore Police Department's child abuse unit is investigating a video that allegedly shows people at Digital Harbor High School having sex in the school building, police and school officials said.
Police said a Digital Harbor teacher reported possible child pornography to police on May 26.
The teacher told police a video was "produced by students who attend the school" and posted to Facebook, where it was viewed hundreds of times, police wrote in an incident report.
In a letter to Digital Harbor families Principal Shannon Mobley wrote that a "cell phone video with sensitive footage of Digital Harbor students" had been seen and shared. A city schools spokeswoman said she could not confirm if the people in the video were students.
"The student did not know that he or she was being filmed and certainly did not give permission to share the video," Mobley wrote in the letter, which was dated June 7.
Mobley urged parents to remind their children that information posted online remains there. She warned that cell phones can be used to "hurt others and even commit serious crimes."
"It's just as problematic to watch something that you don't have permission to see as it is to share something that you don't have permission to share," Mobley wrote.
Mobley did not respond to requests for comment. The teacher who reported the video to police and others familiar with the allegations declined to speak on the record.
Baltimore police are working with the Digital Harbor administration and school police to investigate the video, Capt. Steve Hohman said.
"A lot of young people do not understand that the minute you hit send, you're engaging in child pornography," police Det. Nicole Monroe said.
City schools spokeswoman Edie House Foster said the district has resources on its website that discuss ways to keep young people safe online.
"Now that so many young people have cell phones and access to technology, families and schools must work together to make sure our students understand how to use these tools in a safe and responsible manner," House Foster said in a statement.
Adam Rosenberg, executive director of the Baltimore Child Abuse Center, said he's seen an increase in such incidents at schools. With the prevalence of cell phones, he said, students can easily turn "a consensual yet unwise act into a criminal act."
"Kids shouldn't be having sex in school," Rosenberg said. "It's ridiculous that I have to say this."