Do primary records substantiate the cannibalism rumors from Greely's 1881–84 Arctic expedition, beyond the secondary NPS summary?

claim-greely-arctic-disaster-survivor-ran-us-weather-bureau-1887-1891 mentions "criticism of Greely's leadership and rumors of cannibalism" among the seven survivors. That element currently rests only on a Tier-3 National Park Service biographical summary, not on any primary record. It is the most sensational detail in the note and therefore exactly the kind of surprising/contested claim the sourcing floor says must escalate to Tier 1–2 before it can be asserted as more than a hedged rumor.

What would answer it

• Greely's own account, Three Years of Arctic Service (1894) — the unread primary source, for how he characterized the deaths and the accusations.
• Contemporary newspaper coverage and the 1884 relief-expedition (Winfield Scott Schley) reports, which reportedly recorded evidence of the bodies' condition.
• Later scholarly treatments (e.g. Leonard Guttridge, Ghosts of Cape Sabine, 2000) that weigh the physical and documentary evidence rather than repeating the rumor.

Why it matters

The vivid version of this story — starvation and cannibalism behind the desk of the US weather service — is what makes the "person behind the institution" hop worth telling, but it is also the part on the weakest source. Confirming or bounding the cannibalism claim at primary would let the biographical note keep the detail with proper weight instead of a bare hedge, without letting sensational secondary framing leak into the vault as fact.