(This mission is under“The Way of Flesh)
Head to Donovan’s place and he’ll have two dossiers ready for you. One for Vito Scaletta and the other for Thomas Burke. Pick their dossiers both to unlock their corresponding story missions. You can choose which one would you like to recruit first. Vito's district is the nearest one so let's start with that.
Unlocks the following missions:
Chapter 5A: Work the Man Who Bleeds (Vito Scaletta)
Chapter 5B: The Blade Stained Red (Thomas Burke)