Again from the 'fultonhistory' website, another article on this incident, this time from the Long Island Star Journal of 14 May 1951:
Artist Dies As Flames Destroy Home
A radio actor and artist was burned to death and an Elmhurst couple was seriously injured in a $25,000 blaze which swept through a 12 room home early yesterday in Newtown, Conn. William C. Johnstone, 75, an artist who once played the role of Lamont Cranston in the radio thriller, "The Shadow," died in the flames which destroyed his summer home on Currituck road in Newtown. Jules Towoda, 53, and his wife Susan, 52, of 86-11 Elmhurst Avenue, Elmhurst, were taken to Danbury Hospital for treatment of second degree burns. Mrs. Johnstone, who was partly overcome by smoke, was treated at the scene. At 6 A. M. yesterday, a neighbour, Andrew Sedor, saw flames coming from the house and dashed to warn the occupants. He assisted Mrs. Johnstone and her two guests from the house, but Johnstone was fatally overcome before he could be reached.
Added: I can see newspaper references that support the internet references to the son William having played The Shadow / Lamont Cranston, but not the father. Is it simply a mix-up? The father in the 1940 census described himself as an artist, so at least that fits with the newspaper articles.