I came into the part of the judge freaking out on the prosecution. Can someone please explain what was going on?
I will be doing some research on rule 404B.
Goat
Rule 404(b) generally allows crimes, wrongs, or other "bad" acts evidence to be used for limited purposes, generally "such as proving motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident."
To use ANY 404(b) evidence in a criminal case, the prosecutor needs to tell the defense he's going to do it and give an explanation of what the evidence is and which reason or reasons he believes he will be able to use it for a permitted purpose.
Rule 404(b)(1) specifically prohibits using it for what we call "propensity," for example, prosecution can't use your past murder conviction to show that you regularly shoot/kill people with malice aforethought, or your past DWI to show that you're a habitual drunk driver. Propensity to commit crime is never a permissible purpose. Because every lawyer knows this, they routinely try to spin propensity evidence into some category that gets them into a permissible purpose.
Judges see through that crap and more liberal judges won't allow 404(b) evidence at all, or will greatly limited even permitted uses of the evidence. A more conservative judge might give lawyers more ability to drag this stuff into the trial, but it's a good way to get reversed, so judges generally don't like 404(b) evidence unless it's closely connected to a permitted reason for using it (for example, the person regularly wears a certain type of clothing, which he's also wearing in the robbery while wearing a mask, so we should be able to show that the person regularly wears that type of cargo pants in an effort to show he is the person in the surveillance video).
Ultimately it's an act of connecting a permitted purpose (identifying the defendant) to the evidence (he regularly wears coyote brown cargo pants with that logo on the side).