Plan 1: Raulothim's Psychic Lance. By the time I get to take that spell, I must have had at least one ASI so I'll just take metamagic adept for subtle spell. I just have to know the name of the target and be within 120 feet of them (240 if the second metamagic option I take is distant spell), and it's pretty close to a guaranteed kill vs. a commoner, no murder weapon, and nothing showing that I was there.

Plan 2: Clone. Claim that it's some revolutionary stem cell rejuvenation therapy and sell it to the super-rich. (Though I might make it fail accidentally if it's someone like Murdoch or Kissinger. Payment in advance, no guarantees, and I'll do it on international waters.)