The U.S. Department of Education's Office for Civil Rights also said the Henderson Independent School District punished the student improperly by placing her in a disciplinary program with the student she alleged had attacked her.
The officials had ordered district officials earlier this month to revise its discrimination and sexual harassment policies and clear the student's disciplinary record.
The district had punished the student and her alleged attacker for violating student rules after police concluded the incident was consensual.
American Civil Liberties Union attorney Ariela Migdal said Thursday the district was wrong for not doing its own investigation. District officials didn't return a message seeking comment.