The second NPC boss fight will be found at the Associate Job TIer. This time it won't be someone within la famiglia but someone from the force! You got it, it's time to confront a cop - or in this situation a detective. Detective West seems to have caught on to your actions and you need to snuff him out before things turn too hot to handle.
As usual, every NPC boss fight requires that you use up 20% of what energy you have, so this will vary from player to player depending on how you eke out your points. Aside from the energy requirement, you'll be needing 2 45 cal pistols, a tommy gun, a bulletproof vest and a sedan. These are all items you've used before, so don't worry about finding them. However, for the sake of the forgetful, every item can be acquired via the Inventory section.
Taking out the bosses can be hard if you don't know what you're doing. As a tip, never ever head into a fight with less than a full health bar at your waist. Aside from that, don't be stingy with the use of your consumables - particularly the health kit or the shiv. Trust me, its better to use them up than to lost and fork out lots of money.
Conquering West will earn you a badge as another trophy, and of course the much needed nod from the Godfather.