FBI's 1974 Zodiac Fingerprint Worksheet Revealed

# FBI's 1974 Zodiac Fingerprint Worksheet: What One Heavily Redacted Page Tells Us

Fifty years after the Zodiac Killer terrorized Northern California, the investigation's paper trail continues to surface in fragments — each one a reminder of how much the public still does not know. Among the files released under the ZODIAC archive is a single FBI Laboratory Worksheet, recorded on March 6, 1974, that documents a fingerprint and document examination of a named suspect in the Zodiac homicides. The suspect's name is blacked out. The examiner's name is blacked out. The results, such as they are, are fragmentary and technical. And yet, the document is worth examining closely — because even in its heavily redacted state, it tells us something real about how seriously federal investigators were pursuing the case well into 1974, years after the Zodiac's letters to newspapers had slowed and public attention had begun to drift.

The worksheet carries FBI Laboratory file number 9-49911-179 and laboratory number D-740306021 LL. It was recorded on March 6, 1974, one day after it was received — suggesting the request was treated with some urgency. The examination itself was requested by the Sheriff of Solano County, California, referenced internally as case number V-24564. Solano County sits northeast of San Francisco, adjacent to Napa and Vallejo — both of which were sites of confirmed or suspected Zodiac attacks. That a Solano County Sheriff's request would land on an FBI examiner's desk within 24 hours speaks to the interagency cooperation, however imperfect, that characterized the Zodiac investigation across multiple California jurisdictions.

The type of examination requested is listed as "DOCUMENT - FINGERPRINT," a combined category that indicates investigators submitted both physical documents and fingerprint materials for analysis. This dual focus is significant. The Zodiac was known for sending taunting letters to the San Francisco Chronicle and other outlets, sometimes including pieces of his victims' clothing or cryptographic ciphers. The FBI Laboratory had been involved in analyzing these communications for years. By 1974, the bureau had assembled a body of "NC Zodiac letters" — the notation "NC" likely indicating "no charge" or a specific classification within the lab's filing system — that formed a comparison baseline against which new submissions could be measured.

The worksheet references two key items designated K11 and K12. In FBI laboratory nomenclature, "K" items are "known" samples — materials with an established, attributed source, as opposed to "Q" items, which are questioned or unidentified samples. K11 and K12 are noted as lacking "significant chr. material available for comparison," a phrase likely referring to a shortage of usable characteristic detail, whether in fingerprint ridge patterns, handwriting features, or both. In plain terms: the examiner could not make a definitive match or exclusion from those two items. K12 is further described as a "Week-At-A-Glance Business Reminder notebook" containing known handwriting — and notably, the examiner distinguishes between "writing" and "printing," a distinction that matters considerably in questioned document analysis, since the Zodiac's communications were predominantly hand-printed in block letters rather than written in cursive.

Also submitted for examination were two palm prints, a photograph of the redacted suspect, photocopies of a Solano County Jail record form, and copies of a fingerprint card along with FBI Master form and city record documents — all pertaining to the unnamed individual. The inclusion of jail records and a fingerprint card strongly suggests this suspect had a prior arrest record, and that investigators were attempting to match their prints against latent evidence recovered from Zodiac-related materials or crime scenes. Palm prints, in particular, are notable: they are harder to lift than fingerprints but have been recovered from crime scenes in a number of high-profile cases, and any partial palm print associated with a Zodiac letter or envelope would have represented a major evidentiary development.

The worksheet's finding in item two — "Nothing noted of which suggests additional [material] of value" — reads as a quietly deflating conclusion. It is the language of an examination that came up empty. Whatever hope the Solano County Sheriff had placed in this particular suspect, the FBI Laboratory, at least on this date, could not provide confirmation. The examiner found no fingerprint or document evidence that definitively linked the redacted individual to the Zodiac materials on file.

This outcome fits a broader pattern in the Zodiac investigation. Over the course of more than five years of active investigation, dozens of suspects were identified, fingerprinted, interviewed, and eliminated — or left in an ambiguous limbo where the evidence was insufficient to charge but not conclusive enough to fully clear them. The FBI's role was primarily forensic and supportive, with primary investigative jurisdiction resting with local agencies including the San Francisco Police Department, the Vallejo Police Department, and the Napa County Sheriff. The bureau's laboratory, however, processed physical evidence and provided scientific analysis that local departments lacked the resources or expertise to perform themselves.

What makes this particular worksheet stand out is its date. By early 1974, the Zodiac had not sent a confirmed letter in nearly two years. The last widely accepted communication was a brief postcard sent in January 1974, referencing the film "The Exorcist." Public and media attention had waned. And yet here is the Solano County Sheriff, submitting a suspect's materials to the FBI Laboratory in March of that year, suggesting that behind the scenes, investigators were still actively working leads — still believing an answer might be findable.

The redactions, authorized under standard privacy exemptions that protect the identities of individuals investigated but never charged, mean we cannot know who this suspect was. We cannot know whether they were ever re-examined, ever cleared definitively, or whether their name appears in other documents within the archive. That is the particular frustration of declassified case files: they illuminate the machinery of an investigation without always revealing its conclusions.

For researchers and Zodiac case followers, this worksheet is both a data point and an invitation. Cross-referencing the file numbers, the Solano County case number V-24564, and the laboratory accession date against other known documents in the ZODIAC archive may help establish who was under scrutiny in the winter of 1974 — and whether the FBI's inconclusive findings on March 6 of that year were ever revisited.

— DeClassX