Cameron Todd Willingham, by most accounts, was a son of a bitch. He hit his wife, drank too much, and listened to Slayer. He also loved his three children, which is why it came as such a shock when he was brought up on charges of burning them to death along with the family home. Incendiary: The Willingham Case is a compelling documentary about how he was charged and executed, despite a total lack of evidence indicating he was actually guilty, nor that a crime had even been committed.

How can this be? The movie lays out the case that the guilty party is the outmoded and antiquated field of fire investigation, which often runs counter to scientific facts about fire. There were many points of evidence used to convict Willingham, and the movie lays out several of them, and then has a variety of fire experts (who are true scientists, not pseudoscientists like the “arson investigators” who collected the evidence that convicted Willingham ) debunk every one. It’s pretty scary to think that a man can wake up to his house on fire and his children burning, and end up getting executed for their murders, but that’s why a documentary like this needs to be seen.

And the movie doesn’t fail its subject. Joe Bailey Jr. and Steve Mims, the film’s directors, go heavy on facts and expert testimony and light on heartstring-tugging, without letting the movie get bogged down or boring. This is a movie with a lot of information to convey, and it does it in a briskly entertaining fashion – there’s a surprising amount of humor in the movie, especially at the expense of the Texas politicians complicit in faulty evidence being allowed to lead to a lethal injection.

It might not be possible for a movie to change the world, but Incendiary will probably accomplish the next best thing and make you think about the issues at stake – not just the death penalty and wrongfu conviction, but arson investigation and politics taking precedence over justice.