Jr.

“All right! I have to shield him! 

That murdering madman... 

is my own brother!!”

BATMAN

is an issue of the series World's Finest (Volume 1) with a cover date of June, 1974. 

Synopsis for Superman and Batman: "Wipe the Blood Off My Name"

When several people turn up killed with special boomerangs in Gotham City, the GCPD and Batman start investigating the case of the "Boomerang Killer". During his investigations, Batman comes across Deadman, and they both work together to find the killer. Meanwhile, Clark Kent is assigned to cover the events of the murders in Gotham for the Galaxy Communications channel. Like this, Superman becomes involved in the case and he assists Batman in his investigation.

Superman manages to prevent a couple of murders by the Boomerang Killer and he delivers the evidence he found at each crime scene to the GCPD Headquarters. Batman and Deadman use some of that evidence to track down a man to a mental facility called Willowwood Sanitarium, where they expect to find information about the killer. However, Batman is shocked when he learns the truth about the killer and Superman becomes suspicious when Batman starts protecting the killer. When the Man of Steel asks the Dark Knight why is he protecting the killer, Batman reveals that the killer is in fact his lost elder brother, Thomas Wayne, Jr.

Batman learned that Thomas was three years older than him, but during his early childhood he suffered an accident that left him with permanent brain damage and he had to be locked in Willowwood, for his and society's safety. Unfortunately, Thomas had escaped a few week ago and he was free and apparently has turned into a killer. 

Batman and Superman track down Thomas Jr., but Batman asks Deadman to take control of Superman's body to prevent him from taking his brother to prison without giving him a chance of redemption. 

With Superman incapacitated, Batman tries to talk sense into his brother, but he is unable to reason with him, but he learns that Thomas has been forced to forge the killer boomerangs, because of his forgery skill learned while in Willowwood. With this new information, Batman realizes that Thomas is not the Boomerang Killer. At that moment, Deadman is attacked by a mysterious man, who demolish the place where Batman and Thomas are located. Releasing Superman, The Man of Steel manages to stop the criminal, who is killed by his own wrecking ball. Superman then starts searching for the bodies of Batman and Thomas Jr. among the rubble, but he is only able to find Batman. 

Unknown to them, Deadman had taken possession of Thomas Jr.'s body and he is willing to use it to start a new life.