Am I the first poster?
Well after just seeing it I'm wavering between a 6 and a 7 out of 10. Cops would've been able to find that the blood on the road was human and not from a deer and the garage with the smell of bleach, dead body wrapped up, pool of blood and bullet holes (not to mention the trio's very guilty demeanors) would have tipped the visiting cops off a lot more quickly.
And then throwing the sister who they don't trust in the same room with her "boyfriend" who is bound up? Yeah, nothing could go wrong there.