TULSA, Okla. – Parents of kindergartners at a Tulsa elementary school are upset after a class visitor projected nude pictures of herself on the classroom’s smartboard.

The principal of Owen Elementary School sent letters to parents warning them they “may get questions” about an episode in class recently in which the relative of a student showed up unannounced and apparently wanted to share some pictures, KOKI-TV reports.

She said the images were of a recent class field trip to the zoo that she helped chaperone, but when the teacher plugged her phone in to share the images, it wasn’t all llamas and goats.

MORE NEWS: Know These Before Moving From Cyprus To The UK

“I asked her what part of the body she had seen and she pointed down toward her lap,” parent Kristen Ross said of her daughter, a student in the class. “I had to convince her that she wasn’t in trouble and that she hadn’t done anything wrong.”

The experience left the girl confused with a lot of questions, prompting an uncomfortable conversation, Ross said.

“She should be protected from things like that by her teacher, by her principal,” Ross told KOKI-TV.

The principal wrote that the images were not displayed full screen, and apologized to parents, stressing that the woman who shared the pictures was banned from campus.

Ross doesn’t think that’s good enough.

“I would like there to possibly be a policy in place to check material before or maybe not hook up personal devices of any kind on school property at all,” she told the news site.

MORE NEWS: How to prepare for face-to-face classes

The episode in Tulsa is at least the second incident in recent weeks in which schools inadvertently exposed students to inappropriate sexual images.

Last Thursday, White Hill Middle School officials in Fairfax, California called police on a teacher who accidentally left his laptop connected to an Apple TV unit in his classroom while students were working on a project, the Marin Independent Journal reports.

The teacher was apparently perusing porn sites on his lunch break, and students got quite a show.

White Hill officials were still trying to “piece together what exactly happened,” according to an email from principal David Finnane, but police concluded there was no evidence of a crime.

In both the White Hill and Owen Elementary incidents school officials declined to identify the teacher involved, and the television news stations didn’t bother to investigate on behalf of taxpayers.