The Cisco Grove Incident under-corroborated
Bow-hunter Donald Shrum, lost overnight near Cisco Grove in the Sierra Nevada,
reported being besieged in a tree until dawn by two silver-suited humanoids and
a clanking, segmented 'robot' that emitted a knockout vapor — fending them off
by lighting and hurling his burning clothing and gear — one of the era's most
vivid single-witness close encounters of the third kind.
Cisco Grove tests how much weight a single credible witness can carry. It has
the markers investigators prize — a witness with a sensitive defense job who
hid his identity for years and sought no payment, a detailed and internally
consistent account, and serious attention from NICAP, APRO, and Project Blue
Book — yet essentially no corroboration. It is also unusual for its era in
centering a mechanical/robotic entity, which cuts both ways: distinctive, but
closely mirroring 1960s science-fiction imagery. The corpus's reference point
for 'credible witness, dramatic account, nothing to confirm it.'
Timeline
1964-09-04_evening
Donald Shrum, an Aerojet missile-systems welder, becomes separated from his
hunting party and, as night falls, climbs a tree for safety after seeing a
light he first takes for rescuers. Through the night he reports being
approached by two roughly 5-ft silver-suited humanoids and a darker,
segmented 'robot' with two glowing reddish eyes and a hinged jaw.
witnesses: Donald Shrum (sole witness to the entities)
primary source: NICAP write-up; Torres & Uriarte (2011)
1964-09-04_overnight
The 'robot' reportedly emits a white vapor that makes Shrum nauseous and
briefly unconscious. He drives the entities back through the night by firing
arrows (which reportedly spark on striking the robot) and repeatedly setting
fire to and throwing his clothing, matches, and gear to keep them at bay.
primary source: NICAP; APRO
1964-09-05_dawn
At dawn the entities depart and Shrum makes his way out, rejoining his party.
A companion, Vincent Alvarez, reports having seen a light in the distance
during the night — the only partial corroboration; no one else witnesses the
entities.
witnesses: Vincent Alvarez (distant light only)
primary source: NICAP; UFO Insight
1964-after
Paul Cerny investigates for NICAP and Coral & Jim Lorenzen for APRO; Coral
Lorenzen calls it 'the most spectacular report we have examined.' The case
reaches Project Blue Book. Shrum's arrows are reportedly taken by officers
and not preserved; no physical evidence survives. Shrum keeps his identity
private for years.
witnesses: Paul Cerny (investigator) · Coral Lorenzen (APRO)
primary source: APRO; Torres & Uriarte (2011)
Named personnel
- Donald Shrum — The witness, an Aerojet missile-systems welder with a sensitive defense job who hid his identity for years and declined payment rank at time: primary witness to: the humanoids, the 'robot,' the vapor, and the night-long siege
- Vincent Alvarez — Member of Shrum's hunting party who reported seeing a distant light during the night rank at time: primary witness to: a distant light only — not the entities
- Paul Cerny — NICAP field investigator who interviewed Shrum and found him credible rank at time: role: the principal field investigation
- Coral Lorenzen — APRO co-founder who called it 'the most spectacular report we have examined' rank at time: role: the leading pro-anomaly endorsement
Object — reported
shape
two roughly 5-ft humanoids in silvery/whitish suits, and a darker, segmented mechanical 'robot' with two glowing reddish-orange eyes and a hinged, lighted jaw; an associated light/craft above
size
the humanoids about 5 ft; the robot of similar or shorter stature, described as metallic and jointed
surface features
the robot's reddish glowing eyes and a jaw that opened to emit a white vapor; the humanoids apparently directing or accompanied by it
observed behaviors
- the entities advancing on the treed witness through the night, seemingly trying to dislodge or subdue him
- the robot emitting a white vapor that caused nausea and brief loss of consciousness
- the witness's arrows reportedly sparking or flashing on striking the robot, and the entities recoiling from burning thrown objects — the witness keeping them off by firelight until dawn
Theories that invoke this case (3)
The face-value reading: non-human occupants and a mechanical device besieging a credible witness overnight — a classic CE-3 if the testimony is accepted.
The case's distinctive feature — a clanking, segmented 'robot' acting alongside the humanoids — reads as a non-biological/automaton intelligence, rare for its era.
The deflationary reading the corpus weights: a lost, exhausted, frightened hunter alone overnight, with imagery mirroring 1960s science-fiction robots, and no independent witness to the entities.
Theories that do NOT invoke this case — and why
the entities are described as suited humanoids and a machine, not an animal/cryptid
the case turns on entities and a siege, not on the nature of a light
a single 1964 wilderness encounter, not part of any government-disclosure arc
Conventional explanations advanced — and their status
Misperception / fear-driven elaboration of a night alone in the wilderness
proponents: skeptics
The leading prosaic candidate: a lost, exhausted hunter, hypervigilant and frightened overnight, elaborating ordinary stimuli (animal eyeshine, lights, shadows) into entities — consistent with the absence of any second witness to the beings, though it does not by itself explain the detailed, stable account.
A hoax
proponents: a default skeptical reading
Weakly supported: Shrum held a sensitive defense job, concealed his identity for years, and sought no payment — the usual hoax motives are absent — but the claim cannot be ruled out given the lack of corroboration.
A genuine close encounter
proponents: Paul Cerny / NICAP · Coral Lorenzen / APRO
Investigators found Shrum credible and the account internally consistent and detailed; but it rests on essentially one witness, the only corroboration is Alvarez's distant light, the imagery mirrors contemporary science fiction, and no physical evidence (the arrows) survived.
Where further investigation has leverage
- The original NICAP/APRO case files and any Project Blue Book record, examined for the verbatim account, investigator notes, and consistency over Shrum's retellings.
- Any trace of the physical evidence — the arrows reportedly taken by officers — and documentation of their reported sparking on impact.
- Independent statements from other hunting-party members (beyond Alvarez's distant light) and a site reconstruction, to test for any corroboration of the entities the account otherwise lacks.
Corpus status
under-corroborated
A dramatic, internally consistent, and investigator-credited single-witness close
encounter: Cerny and the Lorenzens found Shrum credible and free of obvious hoax
motive, but there is no independent confirmation of the entities (only a
companion's distant light), the robot-and-silver-suit imagery mirrors 1960s
science-fiction tropes, and no physical evidence survived. The case stands or
falls on one man's word; held under-corroborated.
status history (1)
2026-06-14 · new → under-corroborated
— seeded 2026-06-14 — corpus-growth pass (canonical cases the record lacked)
Threads of evidence
This case is one node in the connections that run across the record. It appears in 1 thread: