Gary L. Stewart Hunts For His Killer Dad in FX's The Most Dangerous Animal of All

What would you do if you thought your father was a serial killer? For most people, the answer might be something along the lines of "never talk about the possibility ever again," but FX's true-crime docuseries The Most Dangerous Animal of All explores a different choice. Based on The New York Times bestselling book of the same name, the series follows Gary L. Stewart's research into the father he never knew who he suspects is the Zodiac Killer.

Yes, you read that correctly: Stewart is convinced that his biological father Earl Van Best, Jr., is the Zodiac Killer, and has spent a total of 12 years collecting evidence that's covered in the docuseries. Admittedly, some of the evidence is pretty damning: the two men seemingly having the same handwriting and fingerprint scar, and there's a 99-percent probability of their DNA matching. It doesn't help that Stewart saw his father's name in one of the Zodiac Killer's ciphers, which were supposed to provide clues to his real identity.

"I often get asked, 'When you first suspected your father was the Zodiac Killer, why didn't you just stop?'" Stewart reveals in the trailer. "Because it was my identity, and it was my story. I just had to know . . . but it wasn't until I started doing my own research that I found out the whole truth."

While no one has ever been able to determine for sure who the infamous serial killer who terrorized California from the late '60s into the '70s is, Stewart seems pretty damn certain it's his father. And if you have an insatiable desire to find out whether he's right or not, FX will drop all four episodes of the docuseries on March 6 and make them available to watch on FX on Hulu the next day.