Players went murderhobo, how do I apply appropriate consequences?

I am running a 5e campaign for four players, all level 10 at the moment, and they have gotten a little big for their britches. I could use some advice on stern but realistic consequences for them.

For some context, they are on the road headed back to a council at a big city to report their findings on cultist activity. An unimportant throwaway NPC from a noble and wealthy family with several guards rode past the party. The party decided to aggressively grill these people for information that they didn’t have, which escalated to the point of the party slaughtering this group of innocents except for one guard they kept alive to interrogate, which is where I ended the session.

Nobody in the party derives any ability from the gods, so divine punishment isn’t really an option. They’re pretty close to a small town on their way, so unless they make some hasty efforts to cover their tracks, it’s pretty feasible that someone could discover this scene. I’m just not sure exactly how to proceed administering some consequences for this behavior. Any advice at all would be most appreciated!

EDIT: Thank you all for the feedback! Had a long day at work and couldn’t keep up here but I will be reading all the comments. To clarify, I absolutely do not want to run a murderhobo table, and I was clear about that with all the players when we started this game. I like the idea of a quick debrief to explain that this is not the game I want to run.