It seems having the server track criminal status could really benefit the mod. I like what Atom821 was saying but in my opinion simplifying it could be more effective.
The question is, do the tier-up weapons/tools appear at an armoury or simply have them appear in an officers inventory?
Low Level (Peacetime I guess)
- Cuffs
- Taser
- (Maybe a Police Key to access cop cars and special areas?)
Medium Level (When a homicide has occurred)
- Cuffs
- Taser
- Sidearm
High Level (Serial Killer/Cop Killed/High ranking official killed)
- Cuffs
- Taser
- Sidearm
- Semi-Auto Rifle
- (City Key to access all doors/vehicles)
If the armoury route is taken, then perhaps the door is permanently locked to all until someone on the server meets a higher level crime criteria and then the door becomes accessible to police.