While Meursault has very little to do as he kills time in his cell, he finds a torn newspaper clipping detailing an unlikely murder that fascinates him:
On it was a news story, the first part of which was missing, but which must have taken place in Czechoslovakia. A man had left a Czech village to seek his fortune. Twenty-five years later, and now rich, he had returned with a wife and a child. […] As a joke he’d had the idea of taking a room. He had shown off his money. During the night his mother and his sister had beaten him to death with a hammer in order to rob him and had thrown his body in the river. The next morning the wife had come to the hotel and, without knowing it, gave away the traveler’s identity. The mother hanged herself. The sister threw herself down a well. I must have read that story a thousand times. On the one hand it wasn’t very likely. On the other, it was perfectly natural. Anyway, I thought the traveler pretty much deserved what he got and that you should never play games.
Meursault frames the story as a parable by including his own takeaway at the end: the traveler “deserved what he got” because "you should never play games." Meursault, however, reveals more about himself than anything else through his obsession with this story: the callousness with which he claims the traveler deserved a brutal death illustrates a brutality, and a lack of value for the life of others, that matches his apathy throughout the novella. His view of familial murder-turned-suicide as "unlikely" yet "natural" is perverse, with the newspaper story appearing almost as a sick joke to the reader.
Meursault's focus on this story also contains a roundabout admission of guilt. Earlier in the novella, Meursault claims, "I had read descriptions of scenes like this in books, and it all seemed like a game to me." Thus, Meursault, now believing one shouldn't play games, demonstrates a growth in his character: he is admitting that a perspective he previously held was wrong.
What's more, the first part of the story is missing. To take away any real conclusion or lesson based on a partial story would be to have an unfounded, potentially incomplete, and misguided view; that does not, however, stop Meursault from making one.