Maybe you can do a case where Orange is called to a mansion for a hearty meal with others, but they'll get killed off one by one until Orange finds the killer.
Characters:
Orange (Detective)
Purple (Police #1)
T. Red (Police #2)
Mint
Blue
Rose (Mansion Owner)
Pink
Green
The Color Killer (Anyone you choose, but not Orange)
Burgundy
Clover
Lime
i'd love it if the color killer was one of the police officers (Purple and T. Red)
as I said in my suggestion, the color killer can be anyone but Orange
After the auditions, you'll eliminate half and be left with twenty
After the semis, you'll eliminate half again, leaving us with ten
In the finals, everyone eliminated can vote for a winner, and you will rank them based on the votes