Always suffocate. Knives and guns leave blood. Make sure you have a reason for your DNA to be in the room or wear a serious “white room” suit. Best to sink the body in water with weights. Never have an accomplice! Ever! A woman will get mad at you for some reason and turn your butt in and a guy will tell his woman and she will get mad at him for some reason. Either way your butt is grass. And make sure you are obeying every traffic law on the books when you are transporting the body or leaving the scene.
That being said, I am way too dumb to get away with murder.
You are right. I knew someone who killed their 90+ year old step father by suffocating him. Almost got away with it too. Their brother ratted them out after three months of spending the insurance money.
Rule #4.... cremation of the old guy would have prevented finding the drugs in his system.
Its funny, the person had no problem with murder, but their religious beliefs prevented them from cremating the body.
As i said earlier....stupid people commit murder.