The mysterious death of Edgar Allan Poe

Was it murder, illness, or injury, that caused Edgar Allan Poe to die at the age of 40? 
The 19th century American author, Edgar Allan Poe, wrote short stories that helped popularise the genre of the detective novel. But Edgar Allan Poe died surrounded by strangers in 1849, under circumstances that remain suspicious  to this very day. A few years ago, a scholar suggested a new cause of death, which might answer the question: What brought about the sudden death of Edgar Allan Poe?