This story was originally published on February 5, 2016.

The U.S. Department of Education's Office for Civil Rights will investigate a Phoenix high school where the rape of a special-needs student is alleged to have occurred during a school dance, according to a letter from the agency.

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The investigation is in response to a complaint from the student's mother accusing Paradise Valley School District of discrimination and retaliation against her for complaining about the district's handling of the alleged crime.

Heidi Peterson claims her daughter was raped at a school function in 2014. A 12 News investigation into the case raised questions about how effectively students were chaperoned at the event, and sparked outrage among some in the community.

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According to a letter to Peterson from the Office for Civil Rights, Peterson is claiming retaliation against her by the district in the form of "sending a private investigator to observe and follow [Peterson's] actions."

The Office for Civil Rights intends a prompt investigation of the complaint, the letter says. If it finds there has been a violation of law, it will attempt "voluntary remedial action" if possible.

If such remedial action can't be arranged, the agency will seek to end federal funding for the district or refer the case to the Department of Justice, according to the letter.

In response to the investigation the Paradise Valley Unified School District released a statement.

"At Paradise Valley Unified School District (PVSchools), our first priority is always for the safety, privacy and well-being of our students. We are cooperating fully with the United States Department of Education Office for Civil Rights inquiry."