The point of Postmortems (or post-incident reviews, since dead bodies are not relevant here) is to learn as much as possible about what happened before, during, and after an incident. The result is everybody has the same shared knowledge. But don't assign blame. Blame discourages people from sharing what really happened.
VictorOps, a tool for incident management, offers a feature for powerful postmortems, in which you can review a timeline of all activity related to an incident, add notes and observations, and share action steps to take in the future.