There used to be a radio show called "The Whistler" where The Whistler told a tale while not preoccupied by his whistling. "The Witness" is sort of a similar character, who might also be compared to DC Comics "Phantom Stranger".
This particular story was originally published in CAPTAIN AMERICA #72 IN 1949. The same issue had Captain America and Golden Girl story "Murder In The Mind", which we had on this blog recently.
Reblogged from http://fourcolorshadows.blogspot.com/
Murder In The Mind ( Captain America story from the same issue ):