you have to get all the clues. You have to get the one from your window, the shootings. Another one from swan park. Another one by running at night. Another one by talking to the flower lady the first time. Another by spending time relaxing and talking to the guy whom lost his sun, bully the answers from him. I think that's all the clues. Then you investigate the mans appartment before your run, and click it's all connected. Butter up the man that comes in and boom, done.
Think it's in chapter 6, it's the second time you get free time. You relax at home then get to talk to Scott in his apartment. Then in chapter 7, your character will want to go for a run and an option will pop up to go to the apartment after or before your run, you want to click on before. Then the it's all connected option, then you butter up the rich dude as much as you can.