‘The Truth About Jim’: Is Jim Mordecai the Zodiac Killer?

The story of the Zodiac Killer is a true crime legend, yet the identity of this notorious murderer remains shrouded in mystery. Now, a new HBO documentary is claiming they may finally have the answer to who the Zodiac Killer was.

The Zodiac Killer is a notorious serial killer who operated in northern California in the 1960s. He terrorized the nation with a string of murders, and cryptic typewritten messages. He sent the letters to the local newspapers, threatening continued violence and taunting investigators to find him.

The Truth About Jim is a new HBO four-part series that focuses on Jim Mordecai, a man who some believe was the true Zodiac Killer. The documentary follows the journey of Jim Mordecai’s step-granddaughter, Sierra Barter, as she delves into the dark family secrets riddled through her family tree. Produced by true crime heavy hitter Skye Borgman, who brought us The Girl In The Picture, Sins Of Our Mother, and Abducted In Plain Sight, the series presents theories that Jim Mordecai may have been more than just an abusive husband and criminal, he may have in fact, been a serial killer.

Who is Jim Mordecai?

Jim Mordecai was a teacher in the San Francisco Bay area. To many, he was a respected educator and member of the community, but to his family, he was something far more sinister. Barter navigates interviews with law enforcement, family members, and others who knew her grandfather, and slowly begins to unravel the dark legacy around Jim Mordecai.

The series revealed Mordecai’s violent behavior towards women and young girls, including physically assaulting his wives and sexually assaulting his 13-year-old stepdaughter, as reported by People. Yet it seems Mordecai’s violent behavior was not limited to only women in his family. He was also known to have assaulted women through the Future Farmers of America organization and others who were close to him. Then, when a string of young women hitchhikers went missing and their remains were subsequently discovered, many signs pointed to Mordecai’s involvement. The group of young women became known as the Santa Rosa Hitchhikers and there were seven in all.

Following Mordecai’s death, the family found a box containing jewelry and other items that seemed to have belonged to the young women. Many serial killers will hold on to “keepsakes” of the victims as momentos, a way to relive their crimes. Mordecai’s family fears that is exactly what they had stumbled across in the box.

Is Jim Mordecai the Zodiac Killer?

While a shocking discovery to say the least, although Mordecai may have indeed been a killer, that does not mean he is the Zodiac Killer. The documentary therefore continues their investigation and finds some striking similarities between the two cases. Mordecai was in the area of the murders, reportedly liked taking long drives, and had the same size shoe as the killer. Sierra Barter, Mordecai’s granddaughter, also felt the physical similarities between the two were significant.

Yet ultimately there seems to be some missing pieces in linking Mordecai to being the Zodiac Killer. For example, all of Mordecai’s known crimes were sexually motivated, while none of the Zodiac Killer’s were reported to be. There is also almost no physical evidence linking him to the crimes or the exact locations. Other theories around the Zodiac Killer do seem far more likely and have far more hard-hitting evidence, even if it is circumstantial.

Mike Butterfield, an expert on the Zodiac Killer, was also interviewed in the documentary and tends to agree that the likelihood of Mordecai being the killer, is low. Yet the possibility of him being responsible for the Santa Rosa Hitchhiking murders is another story entirely.

While Jim Mordecai could hardly be called innocent, it seems likely he’s not guilty on the count of being the Zodiac Killer. While he may be a criminal, a maniac and maybe even a murderer, it does not seem that he is responsible for this particular set of crimes. Yet Sierra Barter has really only just begun her story and with more time and discoveries, she may actually be able to link her step-grandfather, to these terrible crimes, and maybe even more.

The Truth About Jim is now streaming on Max.