Detective Comics#177(1951)

Batman and Robin carry on some investigations on the Batcave laboratory when they realize that some of their equipment is missing. When they go outside to capture some crooks, they are shocked to see the criminals escape using one of their own devices. Upon returning to the cave they learn that in fact, those items are missing as well. Thinking that there might be some criminal who has found the Batcave and is stealing from the place, Batman prepares a series of security measures that would trigger an alarm in case there is an intruder. However, the next day a new item has disappeared from the cave, much to their surprise. Using the inventory, they realize that all the stolen items were used in cases in which the criminal was sentenced to die and that one of them was actually a mistake on their part. The criminal was not executed, but the items were forever tied to that error. Batman goes to investigate the criminal who was spared while Robin stays in the cave to keep guard. Batman gathers some information from the criminal, but when he returns to the cave, he discovers that a new item has been stolen, despite Robin's presence. That night, Bruce realizes that Dick is not on his room and he finds the youngster, sleepwalking on the cave and taking an item with him to the outside. Batman follows Robin to the waterfront, where the boy throws the item on the water. Batman then realizes that Robin's consciousness is not at peace with their past mistake, which almost cost a man's life and he is trying to get rid of the elements involved. After Batman reveals this information to Robin, he also reveals that the criminal who was spared, is in fact guilty of another crime and they got to capture him. By the end of the day, Batman has solved the case of the robberies in the batcave and also fixed a past mistake.