Keep your mouth shut
So, this guy kills another guy during an argument over marijuana. He takes the dead guys body and throws it under another body in a recent grave. The authorities had the following to say.

"Had this guy kept his mouth shut, we would've never, ever found out what happened to this victim," Detective Tony Morales said. CNN

They said he gave some funky information during an interview. Lesson number one when you do something stupid: Keep your mouth shut. The best cover story is "What the hell are you talking about?"