"Red Hood is as smart and well-trained as Batman himself - the only difference is that Red Hood has no qualms whatsoever about killing "underworld scum." The Red Hood mantle is something of a tradition in Gotham's underworld, so Batman's first guess is that this is just another crook looking to make a name for himself. However, after each subsequent encounter with Red Hood, Batman begins to suspect that the murderous vigilante may have a direct connection to a dark chapter in the Batman and Robin Legacy."
January 1, 1970
https://en.wikiquote.org/wiki/Batman%3A_Under_the_Red_Hood