some fish in particular would certainly go after a shrimp. A puffer is the first of many that comes to mind. Of the ones you have listed in your tank I wouldn't normally suspect them of aggression to a shrimp. Except perhaps the maroon clown, they can sometimes just be aggressive in general, IIRC.
There is another option, and that is a crab that you're maybe not aware of in your tank. Often times a crab comes in on LR
as a hitchhiker and are rarely "Good" additions to your tank. Next time the lights go out in the tank and you've shut off your lights in the room, scope around the tank, (use something to give enough light to see without being direct light into the tank) and see if you find any new tankmates.