Confront Doc Gaston

After inflicting all the damage to Doc Gaston’s operations, talk to Detective again to mark the location of the racket boss himself. Make the necessary preparations and head there. Doc Gaston’s racket is found in a huge underground complex with two access points; one is through the front door, the Bigmouth’s bar and take the stairs going to the basement. The other is found in the back alleys northwest of the establishment. In the bar itself, there's a Vargas painting, beside the small stage.

There are two unnamed enforcers in the area as well as a number of sentries, roving, and stationary guards. It is highly recommended to employ stealth here so you can explore the place at your own pace and collect all the cash stacks scattered in the area.

There are a lot of hiding places here which will give you the freedom to sneak behind the shadows in good ambush and stealth kill points. Once you're ready, locate the target in his office. Take out his bodyguards then subdue him to take over this racket. There's also another Vargas painting in his office.