Leonardo DiCaprio has signed his darkest role to date, by far.

Sources are confirming that Leoand his Appian Way partner Jennifer Killoran have secured the rights to the critically acclaimed nonfiction book The Devil in the White City: Murder, Magic And Madness At The Fair That Changed America. The book follows the murders of Dr.
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HH Holmes, known to be the first major serial killer in American history. He's believed to have murdered anywhere between 27 to 200 people aduring the World's Fair in Chicago in 1893.
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Not only is Leo's company producing the flick, but Leo is said to be starring as the infamous killer in the film adaptation. Something tells us he'll be turning to his old friend Martin Scorsese for a little guidance on this one.