The Marshalltown Community School District is investigating a photo where five girls are pictured in blackface, said Superintendent Theron Schutte.

The picture, which was posted on social media, shows the girls wearing black face paint and black clothing.

"We consider our cultural and racial diversity to be one of our greatest strengths in Marshalltown and it's tremendously disappointing that someone in our community, regardless of what their intentions were, would think it’s appropriate," Schutte said.

Three of the girls in the photo attend Marshalltown High School, while another girl attends the district's middle school. The fifth girl is from another school district, Schutte said.

The girls from Marshalltown are still attending school, though Schutte said not all of them immediately returned following Halloween.

The district has talked with several of the girls and will continue to speak with them and their parents, Schutte said. They were not on school grounds or at a school event when the picture was taken, Schutte said.

Student leaders in the district are planning to discuss diversity and how to reach out to the general student population.

"Marshalltown has come a long way in embracing its diversity, but the situation brings to light that we still have a long ways to go helping our youth understand cultural awareness, cultural sensitivity and cultural appreciation," Schutte said.

Some of the girls and their family members issued a statement to the Marshalltown Times-Republican saying "we're sorry" for the incident. None were identified by the paper.

One of the five said: “When I talked to the school, they put it in other peoples’ perspective, and then I saw how bad it looked … we didn’t know what blackface was.”

Blackface originated in the early 19th century when black performers weren't allowed to perform to white audiences, so white performers would use cork or paint to darken their skin. White performers wearing this makeup, which they applied to exaggerate features, ridiculed African Americans. The caricatures in these highly popular minstrel shows, such as "Jim Crow," contributed to a legacy of racist stereotypes.

The newspaper reported that the five girls have been "threatened since the day this has happened," citing one of the girl's mothers. "We, as parents, have sat down with them and talked to them," she reportedly wrote.

What has been difficult for school administrators not only in Marshalltown, but across the nation, is how to respond to incidents that start on social media.

Several racially-charged episodes that Iowa school districts have investigated this year began on social media.

"I think the whole issue with social media is how does what happens on social media then impact what happens in school as it relates student-to-student?" Schutte said. "It's created more situations that need to be investigated and addressed, hopefully as proactive as possible."

The incident is the latest in a number of race-related events linked to Iowa high schools this fall: