I understand why a lot of people are saying they dont like the OP's rules.The constant push for sim rather than RPG in dwarf fortress i think is actually very cool. we're already seeing the beginnings of emergent stories and i say the more work done on that the better. however there will need to be shortcuts, so I suggest this mix-and-match approach.
Procedural crime
poor dwarves, desperate dwarves, dwarves with grudges, all try either sneaking at night or pickpocketing by day, to steal items they feel they need. other crimes eventually,with the highest level of grudge between dwarves with certain personalities, can lead to murder. All of the Fortress Guard now get the job: gathering evidence, interviewing witness, etc. which can be either a series of mini games for the player or maybe just automated jobs.
when the procedurality gets complex enough maybe you could see the natural rise of organised crime in a dwarf fort, e.g Noble bans production of barrels. Dwarves run out of booze. A group of profit minded, non law abiding dwarves decide to build barrels at night and sell them surreptitiously to the brewer, therefore gaining a lot of money to begin their set up as an organised crime ring. but for now it will probably need to be more gamey, untill the simulation becomes a lot more complex.
Master Thief/ Crime Syndicate
you get either a Master Thief or a small crime syndicate clan, in your first emigration after you reach 100 dwarves, with a certain (high) wealth. They will not come if you have less than 100 dwarves, or low wealth, because they need a high population to have any hope of blending in, and because they wouldnt risk coming out to one of these forts unless it has plenty of haul-able loot.