The potatoes contained glycoalkaloids, a chemical component also present in several toxic plants, and had been kept in the basement for a considerable amount of time.
They become poisonous and lethal when kept in storage for an extended period of time or exposed to heat. The toxicity of potatoes increases with age.
Therefore, everyone who went to the basement to get some potatoes was murdered by the poisonous vapors from the potatoes! It may seem spooky, but this is a genuine tale!
