It might be conspiracy to commit murder, or it might be fraud, if he was intending to take the money but not kill anyone. What do the police do when they catch

It might be conspiracy to commit murder, or it might be fraud, if he was intending to take the money but not kill anyone. What do the police do when they catch someone who was selling fake illegal drugs? It can't be a drugs offence, can it? But I'd hope they prosecute them for something.