I recently had two Damsels killed in my tank and am trying to determine the culprit. The tank is an established 150 with ample live rock, dead coral and places to hide. The lighting is on around 13 hours a day, then off all night - which is when the crimes have taken place. Both Damsels had one eye plucked out and were pretty torn up by the time I found them in the morning. Both were killed over 2 days.

The Damsels had been in the tank 7 years and were pretty good sized - 4 inches each
Grouper, 7 inches, friendly has been in the tank 5 years
Tomato clown, 4 inches, has an attitude but keeps to himself, 5 years
Blue Tang, very active, 5 1/2 inches, 5 years
Lionfish, 8 inches (grew very fast), peaceful, 2 years
Lunar Wrasse, 6 1/2 inches, very active, 6 months

I also have two large turbo snails and a very small starfish. I don't suspect them because of their size and speed limitations.

I would appreciate any comments, hunches or suggestions on this matter.
Thanks much!