It is not your job to blame or punish!
Really. If somebody has done something wrong, and he or she refuses to recognize this and does not take any responsibility punishment may be required. But otherwise: you are dealing with professionals working the Safety Process, and your role is to help and support them doing this better every day. You may “know” on paper how things should go, but an organisation is only as good as how things actually are done in the field, and this is an art which you develop together. If the system fails, everybody is a part of that. The only real priority is learning: what went wrong, how could this happen, could it happen elsewhere, what are the solutions, how can we implement that.... those are the relevant questions.