as a professional hit-man, i know where-of i speak.
if you want/need to kill someone in this country, get them on a bike, then hit them with a car.
easy, clean, and zero-risk: if you do kill them, just carry on driving, if you don't kill them, they'll only ask nicely if you'd mind terribly maybe replacing their helmet that they accidentally left in the way of your rear-left wheel…
the best tactic is to use 2 cars, in convoy; the lead car knocks 'em off, the chase car sweeps 'em up!
Mystery; your man was either a cheapskate or an amateur – stopping to check you were dead? – a school boy error!