Moore, who disappeared Friday, was last seen leaving a Greenville bus. Police announced Monday she was missing and said Tuesday her body was found in a trunk dropped from a bridge.
A construction worker found the container, The Dallas Morning News reported Wednesday.
In a letter to parents, Greenville Independent School District Superintendent Don Jeffries expressed condolences to Moore's family and friends, and reminded people to "stay alert for any strange or suspicious person around our school and buses." He said the school district provided police with surveillance video showing Moore safely departing the bus Friday.