As the rule states "Detective: Can look further into a case to make sure someone got robbed reasonably." That being said, it means you can hire a Detective, or someone can hire you (if you are a Detective) to make sure they were robbed properly. They basically look further into robberies or raids I suppose. Most people don't really use this role though.
For the Lawyer...."Lawyer: Almost like a Detective. Can help bandits from getting arrested by making sure there was a valid and proofable case to where the police can arrest the bandit, if the Lawyer wins the bandit has to pay a fee of 200 bamboo to the lawyer!" This role basically just frees people from jail if they find that the police didn't have proper grounds for the arrest.
Rules and Role info can be found here:
http://pandahut.net/forums/viewtopic.php?f=33&t=777
I have a YouTube Channel now. I do a lot of hunting with friends, running around having fun as LAPD Popo, Kill montages, War videos and other random videos. Don't be afraid to stop by, give some comments, subscribe, whatever lol.
Arashi"TheWolf"onYouTube