You see them in the police procedurals all the time: the person every cop turns to when they want to know about the body. I can’t count the number of short scenes in morgues featuring someone kitted out in scrubs tossing around information like time and cause of death.

Obviously, it’s someone with extensive medical knowledge, but that’s where things get complicated. Are they a coroner? A medical examiner? A forensic pathologist?

Most people think of death as an either-or proposition: you’re either dead or alive. I’m not here to dispute that (sorry, zombies!). Instead, I want to talk about what a body goes through immediately after death. These are known as the stages of death or post-mortem changes.

If you’re a mystery writer, you’ve probably written about a medical examiner or detective estimating the time of death based on some or all of these stages. Even if you haven’t, most people have heard the term ‘rigor mortis.’ In fact, that (and a few others) are the go-to ways for investigators to predict when the person died during the early post-mortem interval (up to 72 hours after death).