Officials with Trinity Lutheran Church and School say teacher Laura Perry put together the voluntary project and is a family friend of 55-year-old Rickey Rowlett.
Perry, who allegedly told students Rowlett was falsely accused, is no longer with the school. School administrators said Wednesday that the project was unacceptable and security has been updated.
Jurors in New Braunfels on March 22 sentenced Rowlett to 50 years in prison after his conviction for sexual abuse of a girl. Investigators discovered the letters following the conviction.
Some parents days later filed a negligence lawsuit.
The principal has been put on paid leave. Perry couldn't immediately be reached for comment.