FX’s Docuseries The Most Dangerous Animal of All Irresistibly Considers a Zodiac Killer Theory

As FX, long time purveyor of great cable television, explores its identity in a post-Disney merger world, it has taken two paths. One is to partner with the streaming service Hulu, including (rather confusingly) creating Hulu-exclusive series alongside next-day airings. The other is to lean into documentary series and films, something that premium networks HBO, Showtime, and streamers like Netflix have seen success with. The first of these is The Most Dangerous Animal of All, a brisk four-part docuseries that focuses on Gary Stewart, who—with author Susan Mustafa—wrote a book of the same name detailing why he believes his father was the infamous Zodiac killer.

Along with Jack the Ripper and the Black Dahlia murder, the Zodiac killer remains an unsolved mystery that continues to fascinate and beguile never-ending swaths of armchair sleuths. Zodiac was active in California in the 1960s and 70s, with the slaying of five victims and two survivors that played out across local newspapers, although he claimed to be responsible for well over 30 deaths. Ever since, there have been plenty of people to claim they know the killer, or are the killer, etc. In The Most Dangerous Animal of All, executive producers Ross M. Dinerstein and Kief Davidson present a compelling case for Stewart’s claims before deconstructing some of its most basic attributes. The documentary also makes the interesting choice to only slowly unravel Stewart’s own personality and the part it plays in these claims and the larger story being told. This isn’t just a rehash of the book—it’s an investigation of it.

Stewart is the biological son of Earl Van Best, Jr and Judy Chandler. The two met when Judy was 14 and Van was 27, and ran off together in what became a nationally-reported story of the “ice cream romance.” It was anything but, of course, and Best was arrested multiple times and considered a pedophile. He was also abusive to his child bride and their baby (Stewart), who he would close up in a footlocker when he cried. Ultimately, Stewart was abandoned and adopted into (by all accounts) the loving home of Loyd and Leona Stewart in Baton Rogue, Louisiana. But as Stewart details in the documentary, he learned all of this as part of a lifelong quest to uncover the truth about his parents—which culminated in him believing his father was the Zodiac killer.

Through interviews, archival footage, and and well-considered cinematic reenactments, Dinerstein and Davidson compile an engrossing investigation that walks alongside Stewart’s findings. The evidence is enough to catch the attention of the aforementioned Mustafa, who had gained fame writing true crime books. Based on Stewart’s own work and some of her own, Mustafa felt strongly enough about the case to help Stewart with the book—finding, at the very least, the story of Stewart’s parents’ difficult meeting and his own search (and its toll) an interesting thread to follow. Other investigators and experts they employed in the writing of the book also seemed to agree.

From the start, though, there are clues that Stewart may be a problematic narrator of his own story. We learn (by his own admission) that his obsession over finding his birth parents and his father’s possible Zodiac connection took over his life and ruined several of his ultimately four marriages. He appears to have no compassion for his birth mother, Judy, angrily stating that she had lied to him or been vague about this traumatic event that her family hushed up from over three decades earlier (Stewart first met Judy when he was 39). When his son brings up the gratitude he might feel about escaping his terrible father and being adopted into such a loving home, it’s brushed aside. Ultimately, Stewart has a one-track mind, and it’s focused on the Zodiac killer (and never the victims). The word “obsession” is used quite a bit. “Any identity is better than no identity,” Judy sagely states about her son’s motivations.

The facts that we do have about Earl Van Best, Jr., suggest that he was indeed deeply troubled, but also possibly just a common piece of shit. That kind of everyday evil is frightening enough on its own, but it’s also augmented alongside Zodiac killer facts. Was it Best’s upbringing that contributed to his abusive behavior? Did he use that trauma and later frustrations in life to become a notorious killer? Or are there compelling counterarguments to be made? The documentary seeks to explore and answer this questions in an entertainingly meta way by going over the facts of the book and then stepping outside of it to also consider its authors.

On the whole, the documentary combines a number of niche interests: docuseries, true crime, and the Zodiac killer specifically. Its four-episode counts makes it an easy investment, one whose ultimate turn is bizarre but feels like a perfect fit for this strange case’s natural twists. For FX, it’s also a gamble that this kind of new programming for them will prove popular. But no matter where it, or viewers, land, Mustafa’s instincts were always sound: It’s a heck of a story.

All 4 episodes of The Most Dangerous Animal of All premiere Thursday, March 6th on FX and Hulu.

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