Lawbringer

Lawbringer is a Fallout 3 perk.

Description
Once you have the Lawbringer perk, any evil character you kill will have a Finger on their corpse. This Finger can then be sold to a certain person (whose identity is disclosed when you take the perk) for caps and positive Karma.

The evil alternative to this is the Contract Killer perk.

This perk is required to obtain one of the Guns and Bullets books.

Bugs

 * It is possible that Sonora Cruz vanishes from the Regulator HQ and does not return. Fast traveling to the HQ often spawns either two Yao Guai, two Giant Radscorpion or some combination. They are normally busy killing the Brahmin outside the HQ, however they engage you upon your arrival. Due to the nature of the AI and the NPC characteristics of Sonora Cruz, this causes her to flee from the area.


 * For those ambitious types: If you can collect 1000 or more Fingers there is a glitch you can cash in on.  When selling Sonora any quantity of Fingers above 1000, she will pay you the full amount but only subtract 999 Fingers from your inventory, leaving you with the quantity of Fingers of X-999 in your inventory.  You can then sell her the Fingers "again".  So if you were to sell 1200 Fingers to Sonora she would give you 12,000 caps and you will still have 201 Fingers left in your inventory to sell again, resulting in another 2010 caps profit.


 * If you find the dead body of the regulator (the one containing the hit on Junders Plunkett), look closely, it is a dead body, but you may notice that it is actually blinking. Whether it needs to be a certain time or other such variables is unknown. Initially discovered during night time. (Confirmed on 360)


 * Sonora Cruz sometimes only gives you 5 bottlecaps per Finger.