FX has unleashed the trailer for its new true crime documentary series The Most Dangerous Animal of All. The four-part series is based on the New York Times best-selling novel about Gary L. Stewart who, if you’re not familiar with, is the man that believes his father is the Zodiac killer.

This story is… unreal, to say the least. But the gist of the novel is as follows: After Stewart is contacted by his birthmother for the first time, he decides to look for his biological father. What follows is a ten-year search that leads him to wholeheartedly believe that his father is one of the most notorious killers in American history. The book itself, written by award-winning author and journalist Susan Mustafa, includes interviews with family, friends, and law enforcement, and compares handwriting samples, police sketches, and photographs. By the looks of the trailer, the documentary follows suit.

“I’d ask my biological mother about my father, and she’d say she didn’t remember,” Stewart says in the trailer.

I think it goes without saying that the Zodiac killer’s identity is still officially unknown, but this is still utterly fascinating.

Okay, bad news: You can’t watch the trailer on YouTube because FX isn’t available in Australia, which also means you can’t access the website.

Good news: The trailer is on social media. There are also… other ways to watch the documentary.

The Most Dangerous Animal of All hits FX on March 6. Do what you will with that information.

That last shot made my skin crawl.

You can check out all the details about the book right here, if you’re suddenly very invested.

Image: FX / The Most Dangerous Animal of All