Dark Brotehrhood-"permanent retirment"bugged?(spoilers)

[KaiSardone]

Ok i'm doiugn the "permanant retirment quest for the dark brotherhood. When i goto kill the guy, my eye thing indicates no one can see me(when he's in the water) But no matter where i shoot from i always end up with a bounty on my head afterwards!

Anyone know what the problem might be? or if its just an annoying bug?

[Babytank]

I got the bounty too, but it's no big deal. I just pay the fine and go on with the game.

[Zmurf]

I killed him in his sleep with another guard in the room and I got no bounty. Except the guards back was turned. It was like 3 in the morning or something and he was in the downstairs bedroom.