Fish mystery death possibly by starfish

[Sorcha2]

So I had a fish die recently and I've pretty much elementated everything else but I recently added a small 6-8" across black and white brittle star. So I was wondering if anyone who has had a brittle or serpant star kill a fish could chime in on if their star ate the whole fish, munched on the usual predator spots of belly and eyes, or just chewed off the fins?

 

[DSC reef]

We've kept some very large serpent and brittle stars and never experienced any problems. We did feed them once a week. I'd imagine a sick or dying fish could become easy prey though.