He died because of a Brain Tumor. One of the most recent theories about Poe's death suggests that the author succumbed to a brain tumor, which influenced his behavior before his death. When Poe died, he was buried, rather unceremoniously, in an unmarked grave in a Baltimore graveyard. Taken to Washington College Hospital, Poe slipped in and out of consciousness; he died early on the morning of October 7, reportedly uttering the last words “Lord help my poor soul.” Poe's death left a mystery that has lingered for more than a century. With the publication of three short tales in the 1840s, Poe invented the detective story. Then his own sudden and bizarre death created a real-life mystery, still unsolved after 150 years, as tantalizing as any of his famous stories.