Because the reason for not employing him now does not necessarily have to be the guilt hanging over him. It could be that you think that the appeal process itself might reveal evidence that impacts your decision regardless of the outcome. It could be a question of practicality; why take a difficult decision now when you could take an easy decision in the near future. You may wish to gauge how public opinion does or does not change over the course of the appeal, there are a number of reasons.