The Code Opened Without Naming Its Author

1. A long-lived message

A 340-character cipher attributed to the Zodiac killer resisted a generally accepted solution for decades after its 1969 publication. The symbols were part of communications associated with the case. Reading a message and identifying its sender were separate challenges. Solving one would not automatically solve the other.

The symbols survived long after the immediate headlines.

2. Two puzzles inside one case

The encoded text asked a technical question about arranging and reading symbols. The criminal investigation asked a different question about the person behind the messages and offences. The questions were connected, but a solution to the first could not automatically provide the independent evidence required to settle the second.

A readable message could still have an unidentified sender.

3. A collaborative effort

David Oranchak, Sam Blake and Jarl Van Eycke worked on the puzzle. Their combination of analysis and computing eventually produced readable text. The difficulty lay in explaining the pattern consistently. A convincing solution needed more than a few recognizable words.

The breakthrough needed more than guessing a suspect’s name.

4. The submission

The team submitted its solution to the FBI in December 2020. Oranchak’s public account records coordination before the announcement. Different skills could contribute to examining the same encoded text. The collaboration focused on the message rather than inventing a new suspect.

The first audience was deliberately smaller than the internet.

5. Families first

The public reveal followed time for authorities to notify victims’ families. The solved message was connected to real crimes, not simply an abstract puzzle. Verification concerned whether the reading explained the cipher. It did not turn the decoded words into proof of every claim inside them.

A codebreaking triumph still carried someone else’s grief.

6. Make the solution account for the text

A proposed decoding needs to explain the pattern consistently, rather than recover a few words that support a preferred theory. The successful work could therefore be examined against the cipher itself. That made it a real breakthrough while keeping its achievement narrower than solving every unresolved part of the case.

The decoded words had not signed a confession.

7. The remaining gap

The decryption did not identify the killer. Opening a message and solving the crimes were separate achievements, and the announcement established only the former. The breakthrough answered a genuine historical puzzle. The unresolved identity remained a different question requiring its own evidence.

The words became readable. Their author remained unnamed.

Sources

• David Oranchak — Solution announcement
• Codebreaking team — Detailed solution chronology