The Middleton School District Administration is investigating after learning of the costumes, which were worn during class. Photos were posted to the district's Facebook page Thursday night, though they were later removed.
Superintendent Josh Middleton said in a statement Friday morning that a parent alerted him to the issue. He apologized on behalf of the district.
Middleton is about 34 miles west of Boise, with 7,500 residents. According to U.S. Census Bureau data, nearly 10 percent of Middleton's population are Hispanic, and the school district offers a migrant education program.