It is definitely a possibility - probably a part of the normal diet.
HOWEVER, as anemones have special needs, I would not say that it killed a healthy anemone. It may have taken advantage of a dying one, in which case it is the hero (dead anemones do little for water quality).
However, being "torn apart" does not sound like a seastar. It would be on top, and digests the food by dissolving it. So it doesn't sound like the chocolate chip killed it, but may have been attracted to the smell of it once dead.
How often do you feed your chocolate chip?
How long have you had the anemone, and what lights do you have?