Is it illegal to hire an assassin or order the kidnapping of a person so that he can then be killed and his body disposed of somewhere in the forest?

Would it be illegal to order an assassin to kill a person or kidnap a person and then ask the hitmen to dispose of the body so that no one would ever find it? Let’s say if the killers I hired destroy the victim’s body, then if no one found out about what happened, then nothing happened at all?