predator

[psuedo]

I have been losing some small fish and shrimp lately, as to whom I was baffled. I was blaming it on the arrow crab before, but now even he is gone. When I turned on the light this morning I caught the saron shrimp with someting between its legs. It looked like it had a red tail. 2 minutes later I caught him sneaking up on my most recent percula purchase, but I put my net in to chase him away.
I did not think this possible. I have had him for over a year now and he has had good growth. Only lately have I noticed the fish and inverts disappear. Why did this happen?? Is it possible he got his first taste of blood and went crazy

Other than take my reef apart, how would I remove him from the tank?