FBI's Secret Zodiac Fingerprint Report: What File A-10042 Reveals

# FBI's Secret Zodiac Fingerprint Report: What File A-10042 Reveals

By DeClassX

By the fall of 1969, the Zodiac Killer had already terrorized Northern California for over a year, claimed at least five confirmed lives, and taunted investigators with cipher-filled letters mailed directly to newspapers. Local police in Vallejo, Napa, and San Francisco were struggling to keep pace with a killer who seemed to relish the chase. What has been less publicly understood is just how deeply the Federal Bureau of Investigation had embedded itself in that investigation — and a single declassified page from December 9, 1969 offers a rare, precise window into that involvement.

The document in question is a formal report from the FBI's Identification Division, Latent Fingerprint Section, headquartered in Washington, D.C. On its surface, it is bureaucratic and terse — a routing slip dressed up as a report. But read against the backdrop of one of America's most enduring unsolved murder cases, every line carries weight.

The report is dated December 9, 1969, and carries three distinct identifying numbers: a file number of 9-49911, a latent case number of A-10042, and an exhibit reference of EX-1111. It was addressed to the Special Agent in Charge of the FBI's Chicago field office, and it references two prior exhibits — EX-1042 and EX-1042-2 — connected to an earlier airtel communication sent on November 29, 1969. An airtel, for those unfamiliar with FBI procedure, was an internal priority communication sent between field offices and headquarters, typically used when speed mattered but a full teletype wasn't warranted. The fact that Chicago originated the examination request is itself notable: it suggests that whatever physical evidence was being analyzed had a connection, however indirect, to the Bureau's Chicago division, not solely the California field offices working the case on the ground.

The examination itself was conducted under what the document calls ESCA — a reference that appears twice in the specimens section, both times with language describing subdiced information concerning a "Fallow Examination." The precise meaning of this phrasing, as transcribed, is partially obscured by the document's age and condition, and key portions of the specimens section are outright redacted under the b7c exemption. Under the Freedom of Information Act, b7c redactions protect information compiled for law enforcement purposes that, if disclosed, could reasonably be expected to constitute an unwarranted invasion of personal privacy. In a fingerprint examination context, that typically means the identities of individuals whose prints were submitted for comparison — suspects, persons of interest, or witnesses — have been deliberately withheld.

This is not a trivial detail. In late 1969, the Zodiac investigation had produced a number of partial leads and potential suspects. The killer had sent letters containing taunting clues, and at least one encounter — the October 11, 1969 cab driver murder of Paul Stine in San Francisco — had resulted in witnesses and physical evidence that included a swatch of Stine's bloody shirt mailed to the San Francisco Chronicle by the killer himself. Whether the specimens referenced in this December report relate to that evidence, or to some other physical material entirely, cannot be determined from the declassified page alone. The redactions see to that.

What the document does reveal unmistakably is the institutional breadth of the FBI's internal response. The routing list at the bottom of the page reads like a directory of J. Edgar Hoover's inner circle. Among those receiving copies were Clyde Tolson, Hoover's longtime deputy and confidant; Cartha "Deke" DeLoach, the Bureau's third-ranking official; Mark Felt, who would later become famous as the Watergate source known as "Deep Throat"; and William Sullivan, head of the Domestic Intelligence Division. The presence of these names on a latent fingerprint routing slip is striking. Senior FBI leadership did not typically receive copies of routine forensic reports — their inclusion here suggests this case, or at least this specific examination, was being tracked at the highest levels of the Bureau.

Also notable is the distribution list for physical copies of the report. Two copies went to someone identified as Rosen — referencing two different file designations, 9-68 and 9-59 — and one copy was mailed to the FBI's Los Angeles field office. The Los Angeles office had its own active involvement in Zodiac-adjacent investigations during this period, partly because one of the suspected communication attempts by the killer had touched Southern California. The copy to Los Angeles reinforces that this was not a siloed inquiry but part of a broader, multi-city federal apparatus quietly working in parallel to local law enforcement.

The document was mailed on the same day it was dated — December 9, 1969 — a detail confirmed by the stamped notation "MAILED 24 DEC 9 - 1969," indicating it went out in the 24th mail batch of that day. Handwritten signatures and initials appear at the bottom of the page, the customary sign-off practice for official FBI correspondence of the era, though the identities behind those initials remain unclear in this scan.

Decades of Zodiac research have focused heavily on the California investigations — the Vallejo Police Department, the San Francisco Police Department, and the efforts of detectives like Dave Toschi. The federal dimension of the case has received comparatively less scrutiny, in part because FBI records related to it have been released piecemeal and often heavily redacted. This December 1969 fingerprint report is a reminder that behind the local detective work, a parallel federal investigation was underway, moving at its own pace, governed by its own chain of command, and apparently reporting upward to some of the most powerful figures in American law enforcement history.

The central question this document leaves open is the one it refuses to answer: whose fingerprints were being examined? The b7c redactions that shield that information were applied for legal reasons that remain valid today, which means the identity of at least one individual connected to this forensic examination has never been publicly disclosed. Whether that person was a suspect who was cleared, a witness who was never pursued, or someone whose connection to the Zodiac case remains entirely unknown to the public, is a thread that researchers and investigators may one day be able to pull. For now, FBI Latent Case No. A-10042 stands as one more piece of a puzzle that, more than fifty years later, remains stubbornly incomplete.

--- DeClassX writes about declassified government documents for X-Vault.