Transform is explicitly prohibited from this.
EDM, Usable As Attack (Target moves to afterlife dimension) would simulate the power quite well. However, it is also completely unbalanced.
EDIT:
I thought of this build after going to bed. The auto-kill portion won't work on anyone with Combat Luck unless they are deliberately taking the shot. However, the KA will still severely injure, or possibly kill them if they are hit.
Killing Curse: (Total: 110 Active Cost, 74 Real Cost) Extra-Dimensional Movement (Single Dimension (afterlife, does not work on targets with dimensional movement or applicable luck-based defenses)), Ranged (+1/2), Usable As Attack (+1 1/4) (55 Active Points); Linked (Lethal Damage; -1/2) (Real Cost: 37) plus Killing Attack - Ranged 3 1/2d6 (55 Active Points); Linked (Transport target to afterlife; -1/2) (Real Cost: 37)