The Huntsville City School District is being investigated by the U.S. Department of Education over claims of harassment.
Officials say a JROTC instructor at Grissom High School told students that homosexuality is sinful.
GLBT Advocacy and Youth Services, an Alabama nonprofit, filed a complaint with the Department of Education in October.
In their complaint, the organization says the school district failed to prevent and stop harassment.
The school district received a letter from the department of education this week.