Sure. That's the hope of every defense attorney, that they can create doubt with a mountain of molehills.
realistically, as a murderer he made some mistakes, not an awful lot of mistakes but some serious enough to put him on radar.
His DNA on the button of the sheath being the most serious.
BUT, lets look at how adept he was in his task too.
Let's look at his education and training, his prior exposure to the elements of criminology, basically the entire internet of resources.
they allegedly did not find his VANS and the Van footprint was described as 'light'
this suggests to me that he may have placed plastic bags over his shoes, perhaps more than one bag for each length of his journey to his vehicle and a completely different pair of plastic bags for his drive to wherever he went on his way home, possibly somewhere to stash or destroy all evidence of his night's handiwork.
every description of him I heard described him as pedantic.
i can imagine him planning on the destruction of evidence point by point.
well in advance of his macabre mass murder.
I'm not remotely surprised that no victim blood was found in his apartment.
He'd also be pretty well versed in the use of chemicals for the purpose of destroying evidence and he did actually have an awful lot of time.
JMO