Invisible killer?

Today, I was playing minecraft, but someone had activated a nether portal. It spit out ghasts, I closed it and slain 2 of the ghasts. When that was over, something else happened...
An invisible person was shooting arrows faster than a skeleton could, and he was murdering us all.
I used /spawn to get a away and /home, but he found me over and over, so I logged out. I'm staying logged out until he is gone. I think it MIGHT have been some guy named "Matack", but I'm not sure. I say Matack flying around, but Matack isn't the full name, it had numbers in it. If you guys find out who it is tell me.

[edit]
It might be that crater guy.

I did some searching during this 'event' and found that there's a known bug involving a player manipulating their own death where that player can become invisible and invulnerable. This person obviously knows how to manipulate this bug and was flaunting hir untouchability by posting signs in front of me. I also found that the player did not show up in /who or /playerlist.

This would be another thing that I'd love to see fixed with a workaround until Notch patches it. I'll keep an eye open for anybody named Matak* though.

"It might be that crater guy."

Hell no.

There was someone just today, who killed me, and stole my 38 gold, and 64 of my iron...

I think it was the guy who started attacking me in my house near spawn...

There was a greifer, whom proceeded to log in as another account and -might- have hacked the server. We had tnt going off everywhere..what a mess..

Hm... there had been one guy, who attacked me in my house, so i retaliated, and ended uo "killing" him. Then an invisible stalker-guy started killing me...