I’m not really sure what I should be looking at on your torch. I can kind of see a few indistinguishable little white specks, but that could be anything. Although it’s most likely to be either a grain of sand stuck to a tentacle or possibly a copepod.
Is that little pinkish spot in the bottom left corner of the picture a flatworm? If it is a flatworm, it doesn’t look like the type to eat LPS. If it is a flatworm, it could be type to reproduce enough to smother corals, but if it were the cause of your coral deaths that would be obvious by the hundreds or thousands covering your corals.