Bounty Hunters are people who make a living out of catching criminals for the bounty on their head.
The reasons behind a bounty hunter doing their job is often mixed. Some are hunting down criminals just for money, others to bring them to justice their way and some for fame. Of course, there are also those who hunt down bounties for the challenge they offer as a means of testing their own level of skill. Bounty Hunters also act independently from other established law enforcement groups and are free to roam as they please. They also have no fixed workings and some may hunt solo or with others, making them nomads at best. While they are sometimes no better than criminals themselves, they are left alone to hunt criminals so long as they do not break the law while doing so. Regardless, all criminals apprehended are released into the custody of The Empire dead or alive.
Some bounty hunters act like mercenaries and are hired to do jobs other than tracking down bounties. Even by those with bounties themselves. Slackjaw often kept several mercenary hunters on retainer so as to have more experienced and capable bodyguards ready if he needed a job done outside the bounds of Imperial City where his gang was able to run free.