The Jan. 10 incident began when the warehouse owner gave a woman and her three friends permission to pick through a pile of vegetables that were set to be discarded.
When he came back to check on them several hours later they were dead, RIA Novosti reported.
"There is a strong smell of spoiled tubers, which gives grounds to believe that the deaths were caused by a toxic substance released by rotting potatoes," a police report states.
No precise cause of death has been announced.
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