Batman #338

THIS SPORTING DEATH!

Batman fights the Sportsman, an athletically-costumed murderer who is out to kill famous sports figures. When Batman finally confronts the Sportsman, he learns that the criminal is killing athletes as revenge against his star father's genetic experiments which turned him into an athlete, but also caused him to develop a lethal disease that will kill him in a short time. In the end, Batman manages to capture Sportsman and the killer is taken by the authorities, although he knows there is little hope for him.

KILLER UNDER THE BIG TOP

Robin investigates the murder of Jo-Jo Jones, a member of Hill's Circus and he goes out to track down the real killer, as the evidence points to his good friend Waldo the clown. Robin first suspects that the killer is Lorna Hill, but the evidence also suggests that it could've been Magnificent Melanie, the lion tamer. However, Robin learns otherwise when she that she's planning to marry Waldo and would never hurt him, much less frame him for murder.  Without further clues, Dick Grayson goes to meet Waldo, who is at the hospital and after listening to his version of the story, the whole circus group learns that Jo-Jo Jones planned his own death after he was diagnosed with a lethal disease. When Robin verifies the evidence, he also deduces that Jones was infatuated with Melanie and he wanted to hurt Waldo as part of his revenge before dying by his own hand.