The basis of “The Most Dangerous Animal of All” is one man’s story of why he believes the “Zodiac Killer” is his father. This four-part series, which you can find on Hulu, dives into Gary Stewart’s narrative and why he is convinced that the infamous serial killer is his biological father. 

While much of this documentary series revisits the “Zodiac Killer’s” crimes, it also highlights the story of Stewart’s birth parents and Stewart’s quest to uncover his identity. 

The series opens up on Stewart reconnecting with his birth mother, Judy Gilford, in 2002. Gilford later confirmed that Stewart’s father was Earl Van Best Jr. Van Best was 27 years old when he met 14-year-old Gilford. Newspaper clippings flash on the screen telling the story of the “Ice Cream Romance,” which was truly a story of kidnapping and statutory rape. 

Stewart dedicated years searching for his father before he suspected he was related to the “Zodiac Killer.” When asked why he took his suspicion so far Stewart said, “Because it was my identity, and it was my story. And regardless of the outcome, I just had to know.” 

Susan Mustafa, an author and investigative journalist, worked with Stewart to share his story. She was skeptical of his story at first but found interest in Stewart’s background. Together Stewart and Mustafa investigated the story of Van Best. 

One similarity between the “Zodiac Killer” and Van Best was a fascination with cryptography. 

One of the more confusing scenes in the series is a video of Stewart finding his father’s name in one of the coded letters the “Zodiac Killer” sent to San Francisco newspapers. They also used these letters sent from the “Zodiac Killer” to compare Van Best’s handwriting from Gilford and Van Best’s marriage certificate. 

These are just some of the details Stewart has obsessively collected in the past two decades. His mission to find his father and understand how and why he was abandoned as a baby led Stewart down a spiraling path. 

However, his obsessive behavior led him to lose many relationships, including connection with his birth mother and multiple marriages. 

Stewart published a book in 2014 by the same title of the series. He did not tell Gilford about the book until it was published. 

While Stewart may believe his father was the “Zodiac Killer,” Gilford and criminal experts disagree. None of the points are solid enough for authorities to officially resolve this serial killer case. 

While it is interesting to see the theories that Stewart has dedicated his life to developing, the claims have received pushback from experts and online communities. Mustafa was rightfully upset that Stewart had given her fabricated information that lead her to work on the book with him. 

In the final part of the series the filmmakers fact-check his claims and reveal mistakes in the book. I did enjoy getting roped into Stewart’s fascinating story, but I don’t think his father is the “Zodiac Killer.” In Stewart’s search to find his identity, he failed to recognize that his father was likely just another bad man.