Within the investigation a Journey to the past, finding the third part of the letter is bugged for me. I have watched guides on where the letter is and the chest simply isnt there. Im playing on the Xbox one X.
UPDATE - I searched the whole hopsital again and found in a different chest, So if anyone else is having this problem, i found mine the small room outside Johnathons office.
Thank you so much! I had this issue as well