The Code Killer was a serial murderer in Los Angeles in the 1990s. At the scenes of his crimes and in letters written to the investigators on the case, he wrote the digits 903 472 568, which were believed to be a code.
According to FBI profiler Terry McCaleb, the Code Killer exhibited no preference in victims – killing men, women, and one child – or method – using a gun, a knife, and strangulation. McCaleb also believed that the string of digits was, in fact, not a code at all, but merely the killer's way of frustrating investigators.
In April of 1998, McCaleb finally determined the identify of the Killer, and discovered the meaning of the Code.