- Infect the computer via the normal means
- Connect to a CNC relay and await instructions
- Receive instructions and perform the deed
The most important aspect would be to use a non-persistent compromise so that it leaves no trace when the police arrive and unplug the computer to bring it in for forensic analysis. With the trail ending at this computer and no sign of infection, they have their perp; case closed.
Criminal organizations could even offer a SAAS solution - a kind of "crime as a service", where they rent you the infrastructure of ephemeral compromised machines to use.