A renewed investigation into the identity of the Zodiac Killer has emerged through the new true crime podcast "Killer in the Code," which presents a previously unconsidered suspect: Marvin Margolis, also known as Marvin Merrill. The investigation hinges on a recently proposed solution to one of the Zodiac’s ciphers, known as Z13, developed by Alex Baber, who used artificial intelligence techniques combined with historical data to narrow down potential suspects.

According to Baber, after analyzing over 71 million name combinations that fit the cipher’s parameters and aligning those with the Zodiac’s known characteristics—such as age and geography—Margolis emerged as the lone suspect. Baber’s theory gained traction in part due to the involvement of Ed Giorgio, a retired National Security Agency cryptography expert, who endorsed the solution as a significant breakthrough.

Marvin Margolis was a World War II medic who served at the Battle of Okinawa, where he reportedly suffered a traumatic brain injury and “battlefield neurosis.” After the war, he lived variously in Chicago, Los Angeles, and other locations. Margolis briefly lived with Elizabeth Short, the victim in the infamous “Black Dahlia” murder case, prior to her death in 1947. Police documents from 1949 list Margolis as a “possibly a very good suspect” in Short’s killing, but he was cleared at the time. He died in 1993 without facing new scrutiny.

The podcast argues that Margolis was deeply affected by his wartime experiences and harbored resentment toward the military establishment for not awarding him a Purple Heart. He also reportedly had access to cryptographic knowledge through a former military cryptographer with whom he lived. These elements align with the profile of the Zodiac Killer and provide context for why Margolis might have created the complex ciphers used in the Zodiac’s communications.

However, not all experts and commentators are convinced. Criticism has arisen regarding Baber’s solution to the Z13 cipher, which some cryptographers deem mathematically unsolvable due to its short length and ambiguity. David Ornachak, a software developer and member of a team that solved another Zodiac cipher, dismissed Baber’s work as relying on confirmation bias and questioned Baber’s credibility based on past legal and professional controversies.

Journalist Elon Green and others have challenged the podcast’s portrayal of Margolis, noting inconsistencies such as Margolis’s whereabouts during the time of the Zodiac killings and arguing that his name change was motivated by attempts to evade antisemitism rather than law enforcement. Critics have also raised concerns about the impact the renewed suspicion will have on Margolis’s living descendants.

The podcast’s narrator, author Michael Connelly, maintains that the project was borne from genuine investigative interest rather than profit motives and that the second season of "Killer in the Code" seeks to present evidence suitable to convince a jury of Margolis’s guilt.

Despite these efforts, the case remains unresolved, with other prominent theories continuing to circulate. Previous suspects such as Arthur Leigh Allen and Lawrence Kane retain followings, while former Los Angeles detective Steve Hodel continues to advocate for his theory involving his late father, Dr. George H. Hodel, as both the Zodiac and Black Dahlia killer.

Meanwhile, filmmakers behind an upcoming documentary, "Deconstructing Dahlia," announced the discovery of forensic evidence near the scene of Elizabeth Short’s murder that rules out Margolis as a suspect, as well as other leading theories, claiming to identify the real perpetrator without revealing the name.

As cold cases like these persist, the passage of time and fading evidence challenge the possibility of a definitive resolution. Still, renewed public interest and advances in forensic and cryptographic methods continue to drive efforts for closure in some of California’s most notorious unsolved crimes.