So you'd think that vampires, who are the prime suspect whenever someone is found with bite marks on their neck, would not be allowed to exist in society so freely. I mean, the teacher just profiled the girl because of her race, so either vampires are known to go around biting, or people think vampires go around biting. I'd imagine that a species with that kind of reputation would have to be kind of low key about it.
Like really, the conversation literally went "Hey Mr & Mrs Vampire, we think there's a possibility that your daughter has just bit a classmate, potentially changing the course of the rest of their life." If it was a vampire bite, that boy's future may have been ruined, but the whole matter is treated with the urgency of one regular human child biting another.