On October 4, 2021, a group of investigators calling themselves the "Case Breakers" proposed a solution to the case of the San Francisco Zodiac killer. This solution was publicly rebuffed by the FBI, which issued a statement saying that despite the efforts of this group, the Zodiac case remains unsolved. True crime author and researcher, Mike Rodelli, released his book, In the Shadow of Mt. Diablo: The Shocking True Identity of the Zodiac Killer, in May 2021 proposing his own solution to the Zodiac mystery.