Is Libel suit an option?

I have a friend who is a teacher and coach. He has recently had false accusations brought against him by some troubled students who don't like him. He was alleged by the students to have made racist comments, and, since the school superintendent is new and is African American himself, I assume he wanted to be seen as tough in this situation. With very little investigation, he suspended the teacher without pay (while the investigation was ongoing), and eventually tranferred him to another school and banned him from coaching in the school system. The superintedents decisions are allowed by County rule without any checks and balances, so they are final, and the teacher can only appeal to the rest of the school board for 10 days without pay he lost. The biggest problem with the situation, however, is that the superintendent released every letter and memo to the teacher to the local news, which has ruined the great reputation he has built over his past 15 years in the school system. I understand that general public record is not eligible for libel claims, but are these letters and memos public record? In them, the superintendent states as a matter of fact that he is disappointed with the teacher's conduct and that it is conduct unbecoming of a role model such as a coach, comments that assume guilt despite the weak investigation. Is there a libel case or a case of any kind here?

No they are not.

If someone publicly says or writes anything factually untrue and it damages you, you indeed can sue for slander, libel, defamation, interference with business relations etc. -- or at least threaten to do so and give a warning.