Detective Comics #458 (1976)

At a costume fundraiser, a man dressed as Batman dies in Bruce Wayne's arms. His cowl is removed, and he is identified as Lt. Bucky Dunlop; the words "The Real Batman Dies Next!" appear to have been tattooed on his forehead. Gordon is there, and orders all in attendance, including Bruce, to remain behind. As Bruce checks into a hotel room, he realizes that the man had been shot by a gun with silencer. In his hotel, he calls Alfred, who patches him through to Gordon to tell him what happened. As Batman, he tells Gordon that he won't appear, as Dunlop's murder indicates he is the next target. Batman then goes to the Dunlop family, and tells them that Bucky is missing, unable to tell them the truth. Mrs. Dunlop tells Batman that he and Slats Johnson, a friend and ex-convict who owns a tattoo parlor, volunteer every Thursday as part of a juvenile rehabilitation program. Meanwhile, Gordon and the police find a rifle, rigged to fire by remote, in the ceiling; they also learn that the tattoo ink used on Dunlop is a kind of invisible ink that disappears with heat, meaning that he could have been tattooed at any time. Batman returns to the hotel and redresses as Bruce; he then finds Gordon and drops a hint about volunteer work, which leads Gordon to investigate any contacts from that program. Three are found - Johnson, Fellman, and Squire, all of whom Bruce recognizes from his crime fighting. Bruce changes again to Batman, planning to investigate all three men; he goes to Johnson's apartment, where he finds his tattoo equipment, unused. Batman then goes to Fellman's place and discovers a recently opened can that he finds suspicious, and takes it to run some tests. Slats Johnson is arrested for the crime, but pleads his innocence. The rest are set free, but Batman captures captures Fellman and brings him to Gordon, telling him that Slats is innocent, as his tattoo work is different from the calligraphy used in the crime. Fellman, conversely, studied calligraphy during his prison time; Batman then mentions the disappearing skin dye was found at Fellman's place. Fellman is arrested, and Slats is set free.