There was a Doctor Who novel, I think this one, The Murder Game by Steve Lyons, where there was an "Assassination program"... a sophisticated malware package that just required to be configured with the victim's name, and it would search out means to physically kill them via computer-controlled objects.
I'm no expert, but even today it sounds almost possible. You need: (1) a way of tying victims to physical objects and locations (DMV records, toy purchases, planning permission applications, ... ), (2) hacks for physical objects (cars, street lights, Mindstorm Legos, home automation systems, ...),
(3) a worm/virus base to spread the code to computer systems physically near the objects.
If that sounds like an implausible engineering effort, remember that malware packages are incrementally improved on and made more powerful over time... it would start out with some simple and unlikely-to-succeed algorithms, and evolve into something with a huge array of killing options.
(Maybe at that point people would start taking privacy seriously.)