From Rocklopedia Fakebandica
WHIZ lets him take over anyone's time slot he wants, so he takes news reporter Billy Batson's (Captain Marvel). He's such an ass about it, that when Batson tries to talk him out of it, Batson ends up trying to strangle him. When Batson discovers him shot dead shortly after, he's accused of Johnson's murder.
They discover it was really ventriloquist Franzon, who hated Johnson because he drove him off the radio. When Johnson offered him a small spot on his show, Franzon went mad and killed him.