How is the story structured in LA Noire?
The story of L.A. Noire is structured as following:
- Patrol Desk
- Traffic Desk
- Homicide Desk
- Vice Desk
- Arson Desk
In that order, which represents Cole Phelps' career within the police force.
As for why you can play cases from the Vice and Arson Desks, I'm not sure. My guess is that they're DLC cases and you somehow managed to gain access to them early.
While playing the game on PS3 (no DLCs) I've never been able to access any of the future cases.
Currently, I'm playing the game on Switch. I'm at the end of the Homicide Desk and I still can't access any of the cases from the Vice or Arson Desks.
Therefore, I'm going to assume that the game isn't supposed to work this way. Or maybe the Complete Edition works differently from the versions I've played.