Franklin D Roosevelt, the US wartime President's death in 1945 was a mystery that seems to have gotten solved now.

A book named 'FDR's Deadly Secret' written by Steven Lomazow and Eric Fettmann, coming out in January, claims that the President suffered from "melanoma", a type of cancer. This cancer travelled to his brain and abdomen.

The author said that this book is based on mere observation and not physical evidence because the medical records disappeared soon after his death.

The authors also analyzed the original text at President's historic place to see how the words were laid out. And they examined this text and said,"We discovered that the mistakes he made were almost all on the left side of the text of the left side of words. This indicates a condition called hemianopsia, which happens when you have a tumour on the right side of your brain and you lose the left field of vision".