I was going to suggest this may be similar to the glitch kidtsunami and I have experienced, but who knows? http://destiny.bungie.org/forum/index.php?id=29486

Seems odd, yet repeatable enough though. Saying that, I never experienced something like this in crucible myself.

A lot of on the fly patching happening yesterday.

I wonder if that guy was getting kills popping up on his screen and saying "WTF, there's no one here?"

I was playing Crucible on the Moon, and at this particular moment in time, the enemy had zones A and B, and we had zone C. I left C and made my way over to B in order to capture it. There was no one around so I figured that I would capture it without issue. All of the sudden, my screen shook violently and my health went down a good bit (almost as if someone had meleed me). I looked around, saw no one, and then my screen shook again and I died. When the camera looked at my killer, he was over by A spawn crouch walking. The game said that I had died from a melee.

"Weird" I though, I wasn't getting any lag. I made my way towards B again and saw a teammate capturing it. All of a sudden he dropped dead and it said he died from a melee on my screen. I ran down and jumped into B and immediately got double meleed again. For a second time, the camera pointed at the person who killed me and he was clear on the other side of the map. He was in a different area of the A base, but I could see him clearly moving around the map (No lag in sight).

I still have no idea what happened or how this person killed me. I just thought it would be a good idea to mention it.

Note: There was no one else in or around the base and I was not lagging at all that game. When looking at the person who killed me, he was running around the map by zone A in a way that suggested that he really was over there. Really strange.

Hunters use a knife for their melee attack and they can get the ability to throw it, and it even uses the same button as the standard melee. Could that have been it?