As above, if it isn't suicide, then they're looking for another killer. hmmm... who could it be, wonders Doakes? Who had motive?
I may be wrong, having only watched it once, but wasn't Rudy saran-wrapped when he was killed? That would lead to an absence of blood on his shirt, and on his shirtsleeve from the cut. The blood pattern from the level table and initial cut would be fairly evident -- you'd be able to follow the drip/spatter pattern to the inverted drainage position. Also, a cut deep enough to cause fatal bleeding is going to need to hit a major vein or artery. That creates a bit of spurting, at least at first. A forensic analyst would be looking at where that blood landed. Is it where it's supposed to be? Is there a spatter-shadow that would indicate someone else was there?
Of course, this is all premised on the cops being interested in anything other than a tidy package.
Never mind, this is nitpicking a terrific show.