Who is eating my Shrimps?

[ALang]

I have these in a 133 gal reef tank:
2 percula clowns
2 Lubbock's wrasses
9 Blue green chromis
1 Orchid dottyback
1 yellow tang
1 lawnmower blenny
I sand-shifting amblygobius goby
3 yellow tailed azure damsel fish
1 6-line wrasse
1 two spot wrasse -Halicheres biocellatus
1 yellow-tail Indian angel
1 cherub angel
1 mandarin goby
1 flame hawkfish ( I know, but it is only 3/4" long!)
1 yellow-headed jawfish
1 PJ cardinal fish

The only thing that I can think of is the flame hawkfish. I read that you should introduce the shrimps first ( Skunk Cleaners) prior to adding the hawk. I have both med and large-sized ones in there, one day after I brought the flame hawk home. A week later, not even a white whisker in sight! No shells, bodies, nada.
Altogether, 5 cleaner shrimps totally disappeared. Looked everywhere. I really like to try again before the flame hawk gets too much bigger. Any suggestions?