Get this in Chapter 5, after you get off the train at Laxton Station head west and enter the first door. Go to the basement and search the body for an ID. Then in Chapter 6 you learn that Ryan's brother Nathan was the killer, and that people on Ravina Street may have known him. In Chapter 7, take the train to Ravina Street and talk to everyone. You'll need Advanced Charisma to get all the answers you need. This completes the task, but leaves an option to use the knowledge against Nathan open.