My party members just murdered a shop keeper...

[Harkoth]

As a player, it is no fun playing with a bunch of people who think roleplaying is simply choosing slash or pierce based on your mood. Sometimes the party just needs a little guidance and they remember roleplaying is more fun than video game style looting.

As a DM, when the players want to turn in to bloodthirsty thugs... there are consequences. Big ones. This shopkeeper should turn out to be the brother-in-law of the biggest crime boss in that whole galaxy. The next guy they murder will be the son-in-law of a very high ranking military commander or rebellion or whatever authority has the potential to make life hard. And, of course, somehow these big guys learn of the crimes and who committed them. It's the same way you train a puppy not to crap on the floor. A loud sound and a hard enough whack to be uncomfortable before tossing outside. Once the players spend enough time outside in the cold, they'll figure out on their own that skills will get them farther than murder and plunder, and they'll probably start having more fun too.