Short story in which notorious safe-cracker retires but has to use old tools to save girl's life

Question

I remember reading a short story, many years ago, about a notorious safe-cracker in the old west, who managed to accrue a nice fortune by utilizing his skills. I cannot remember the title or author, or the names of any of the characters. I remember it took about two days to get through the entire story, as my class was reading it in school, so I imagine it was on the longer side of "short".

In the story, the man robs a bank and immediately skips town. He goes to a new town to scope out the bank there, under the guise of a traveling shoe salesman. He meets the bank owner's daughter, and decides to try and use her to get information about the bank's safes and vault, but through the course of the story ends up falling in love with the woman and decides to become a legitimate businessman and put away his drills and stethoscope for good. One day, the bank gets a new safe, and, while the adults are talking about it, a young girl, who is playing with some other children, hides in the new safe and accidentally closes the door, which automatically locks. Before they discover the girl, a detective who had been tracking the thief for several months walks into the bank, and spooks the man. He collects his tools in a bag and attempts to escape, but as he's walking through the main hall of the bank, they discover that the girl is in the safe. He decides to sacrifice his own freedom to save the girl, and then the detective, who saw the whole thing, decides to let him go.

Answer 1

This is "A Retrieved Reformation", a short O. Henry story.

From Wikipedia:

Safecracker Jimmy Valentine was released from prison after serving less than ten months of a four year sentence, due to his criminal connections. He goes to his old apartment, packs up his tools, and leaves. In the following weeks, a few cash robberies are committed, and the detective who landed Valentine in jail in the first place, Ben Price, is called to work on the new case. He realizes that the robberies are committed in Jimmy's style. [...] [Jimmy] moves into the town, taking up the identity of Ralph D. Spencer, a shoemaker: he had been assigned shoemaking as forced labor in prison.

[...] Carrying the tool case, Jimmy watches as Annabel's father shows them the bank's new safe. Annabel's nieces are fascinated by it, and as they are playing, one accidentally shuts the other inside and locks the door, without the time lock's clock having been wound nor any combination set. Everyone panics, and Annabel begs Jimmy to do something. Jimmy, knowing that it will reveal his true identity, uses his case of tools to open the door and save the child. Unbeknownst to Valentine at that time, Price has witnessed the whole incident.

Valentine starts to leave the bank afterwards, and he sees Price standing by the door. Sheepishly, he gives himself up, but much to his surprise, Price pretends not to recognize him and walks away.

Found with the Google search query short story bank robber safe girl shoe, but I also remembered the story - having seen it in another question on this site, as it turns out.