Yeah, I really don't know what's going on here, but it's one of the most unusual comic book covers I've ever seen. Also one of the creepiest, despite (or maybe because of) the blotchy photography and the odd perspective. Namely, what the hell is Casey looking at that's more interesting than a clown pointing a gun at him?
Marvel Comics released four issues of CASEY, CRIME PHOTOGRAPHER, of which this is #2, cover-dated October 1949. The cover story was "The Sinister Carnival" (I'll say), and it was drawn by the barely remembered Vernon Henkel, who worked on a couple dozen Marvel titles during the early 1950s. It's possible Stan Lee wrote the story, but no one seems to know for sure.
CASEY, CRIME PHOTOGRAPHER was based on a then-popular radio series about "Flashgun" Casey, a newsman with a nose for finding trouble. Later, after the Marvel comic was cancelled, CASEY moved to television with notable leading man Darren McGavin (best known as KOLCHAK: THE NIGHT STALKER) playing the role, but CBS quickly canceled the series. And, according to McGavin, deservedly so. I wonder if he got to fight any evil clowns?
By the way, that is not McGavin playing Casey on the cover, and I doubt it's Staats Cotsworth, who starred in the radio series.