I've been especially enjoying Quality Comics' Ken Shannon comics. Ken Shannon is a private eye and these are detective stories with Ken usually having to solve a murder. The funny thing I've been noticing is how often Ken just sort of stumbles into the cases. Rarely does he have a someone actually walk into his office and hire him. The Ken Shannon comics also have a humorous detective series, Angles O'Day, which was written and drawn by Jack (Plastic Man) Cole.
Before that, I was reading The Saint comics put out by Avon Comics. The early issues featured very good stories that were true to the character in the books, and makes me wonder if Leslie Charteris actually wrote them, or at least had approval on the stories. And the artist's rendering of Simon Templar bears a striking resemblance to Roger Moore, which is especially curious, considering these stories pre-dated the TV show by more than a decade! The later comics apparently reprinted the Saint comic strip.
As a mystery reader, I was always disappointed by the relative scarcity of mystery comic books (I became interested in comics in 1978), so I'm thrilled to find these older mystery comics.