As I read it, you seem to be saying you don't believe the PCA because the facts do not seem to be the actions of a perfectly rational, logical person.Respectfully, I am not a family member, but in the context of presumption of innocence, I, too, have questions.
We don't know who killed them yet. BK stands accused. I don't believe MPD framed anyone, they merely followed the leads and made conclusions based on crime scene, DNA, the digital data, and the witness' report. With the information they had, they did professional job. If there is a sheath lying on the victim's bed with someone's DNA, they have to investigate the DNA, and follow the DNA owner. We, the public, have to rely on the affidavit. And here are some things that I can't understand.
I tend to agree with @drmrgrl in that the sheath with DNA lying on the bed is almost too easy. If it was BK's, why isn't it covered in his DNA? Why one spot? But maybe, there are explanations to this.
Here is what I can't get.
The murderer, probably, came for one target and overkilled + 3 - on two floors! He is horribly cruel. Did he, for example, start on floor 3, then suspected that someone heard him on floor 2, and went down to eliminate the witnesses? He killed someone who merely heard sounds and said, "there is someone there" . The murderer kills someone hearing him, and others, who were sleeping, not even true witnesses. But then, he bypasses a bona fide eyewitness staring at him with eyes wide open! It doesn't make any sense. Having killed four, you don't leave the fifth, in fact, the only true witness.
Then, he allegedly returns at 9:20 am - to retrieve his sheath, I'd imagine. Why doesn't he get it back? Knowing this sheath might be his undoing. There is no police around. There are no people around house. Why not come in and get the sheath? All he needed to do was to go via the same doors on the 3d floor, and back. Makes no sense, unless something or someone scared him. Then, what and whom? We don't hear about it. We hear nothing about the doings in the house between the killer departing and the police emerging. Everything is so quiet that the killer can't get his sheath.
I hope it gets known during the trial, but so far, question mark. Too many unanswered questions.
(Nothing changes if the target was on floor 2. He kills two people, then passes by a witness who saw him, and goes up to deal with two women, for having heard him, and a barely barking dog).
IMO there are two problems with this: firstly, that a person committing 4 murders during a 15 minute time must be, has to be completely rational and logical throughout that entire 15 minutes.
Secondly, I think a PCA is a fascinating kind of document, that we only see in this kind of situation ie murder.
We don't (thank goodness), have highly skilled people investigating and recording our every action throughout our own lives. Believe me, if you were to read a statement about my actions, you'd be exclaiming 'she walked right past the keys she was supposedly looking for! I can't believe it! Look at that, she typed up a great long email and then couldn't find the email address and ended up phoning them instead! This is impossible....' and on and on.