Letter Scraps - Collect all 50 Letter Scraps
Before you head in and trigger the mission, be sure to shoot out the tires of the car in front of the house. Dreyfuss will go for an escape and makes it easier to achieve Gold. That or attach a sticky bomb to it for a quick end.
With all the scraps, head to the new "?" available to Franklin. There you will find Dreyfuss. He things Franklin is there for something else. When he shows him a photo of Lenora Johnson, it becomes clear and he runs.
You can either let him go or kill him. If you are after Gold, Dreyfuss must die. Either shoot him as he runs away or take him out in his car in some fashion.