First off, bloody diarrhea IS a symptom of radiation poisoning.
Second, if they stole enough enriched material, they could generate a criticality. My brother used to work in a nuclear fuel processing plant, and damn near had a heart attack when he saw some workers using fuel slugs as poker chips--one guy was winning bigtime, and he made a criticality big enough to give him his industry lifetime dose several times over.
Without a doubt.
Sorry, but not in isolation. If there is "bloody diarrhea" there will be other bleeding (and other symptoms) as well. This is the point that the "radiation poisoning" nutcases always miss--they pick on one isolated symptom in the absence of the other symptoms, and claim that it proves radiation poisoning. Also, the claim is that these folks got their exposure by using the storage barrels as water containers (i.e. the dose comes from ingestion). If that was true and they had ingested sufficient to cause hemorrhagic symptoms in that short a time frame, their urine and feces would be "hot", easily measurable with a Geiger counter.
"Second, if they stole enough enriched material, they could generate a criticality. My brother used to work in a nuclear fuel processing plant, and damn near had a heart attack when he saw some workers using fuel slugs as poker chips--one guy was winning bigtime, and he made a criticality big enough to give him his industry lifetime dose several times over."
As I understand it, the stuff in the barrels was "yellow cake", not nuclear fuel slugs--no way to generate a criticality with it. Those "fuel slugs" in the "poker game" must have been pretty damned highly enriched, as enough normal fuel rods to generate a critical condition take up quite a bit more space.