The reality is that you can't shovel the death of a person - too hard to hide. Where he screwed up big time was in talking about what he wanted to do ahead of time. He shouldn't have said anything to anyone. If I were going to bait a trap for a burglar, I wouldn't even tell my wife. What other people don't know they can't testify to in court.
I guess we should add third comandment to:
- Thou shalt not ever consent to a search by police
- Thou shalt not ever talk to police
- Thou shalt no ever tell anyone your plans to do anything that might land you in court.