AC 3 disappearing man?

I was just running aroun the frontier collecting feathers and treasure when I came to this small island, Great Piece Hills i think. There was an NPC crouched on this rock and as soon as i got close to him, he jumped in the water and never surfaced. Anyone know what it might be?

it could be a glitch.

Yeah more than likely a glitch. Ive been playing AC3 for a few days now and ive hit a few glitches and bugs. The game is great and im having a blast with it but it definitely needed more polishing. Ubisoft will probably have them corrected through title updates shortly...

Same thing happened to me. Very curious/ominous. I had a feeling I was being watched by a creepy French settler/templar NPC. It was strange.