Because he didn't have to. Brendan Dassey was a terrible witness, so the prosecutor didn't call him. Guess what? That kind of thing happens all the time. You find you have the case in the bag, you don't present all of the evidence that's available. Every day in this country that's done. Nothing sinister about it, and in fact, there is nothing wrong with it, AT ALL.
There is no way that Dassey or Avery could clean up the bedroom to remove all of Halbach's DNA if they had murdered her there, as the DA claimed.
I'll be willing to consider this claim as soon as you show me your bona fides as an expert witness. Since you aren't one, I'm calling BS.
Absolutely NO DNA. After supposedly having her throat cut.
Supposedly according to whom? Brendan Dassey? NO ONE believed Brendan Dassey's account of the crime.
Why didn't the defense raise this issue at trial? Because they knew the prosecutor would be able to slap them down with a limitless number of forensic scientists who would have told them that there are lots of ways to suppress blood spatter that don't produce the kind of effect they're trying to insinuate in this film, and furthermore, other than the bullet fragment(s) [yes, there were more than one] we do not know how Teresa Halbach actually died.
This is what you don't get: in a courtroom, the evidence is examined. The defense can't just say any stupid thing in the world and have twelve gullible people believe it. The prosecution is going to impugn the testimony of their witnesses. It's going to demolish the credibility of their forensic claims. Many of these claims were only made in the film because the defense knew full well that had they been aired in open court they would have been destroyed.
“NO ONE believed Brendan Dassey’s account of the crime.”
Right. Yet he was convicted of murder.
Yes the evidence is examined. By the jurors. From Manitowok County.