HomeRunBaker said:
I disagree in this instance. If they recover the gun in a random pond in Bristol, CT based on Wallace's cooperation it adds a TON of credibility to this witness. Without Wallace helping them locate the weapon a homeless guy nicknamed "Hobo" is going to get torn apart on the stand. Prosecutors need to be able to say, "We did not have a clue as to where the murder weapon was located until Wallace agreed to cooperate and tell us precisely what he did with the murder weapon following witnessing AH shoot and kill Odin Lloyd." THIS would be a powerful statement in adding credibility to this scumbag which in this case carries more weight than simply locating a murder weapon.
It looks like they are really working on tying additional murder charges on AH here to portray him as essentially a serial killer and not an OJ/Lewis who has a decent risk of walking without a more solid case.
If they recover the gun it does add some credibility.
Best case for the state: the gun matches the bullets taken from Lloyd's body, and it has AH's DNA on it.
If it's the murder weapon, but there's no DNA/Fingerprint/Ownership match, the argument is still the accomplice shot Lloyd and rolled on AH to save his own skin. (However, AH still goes down under Accomplice theory.)
If there's no conclusive ballistics match and nothing to definitively tie AH to it, the defense argument will be that it's just a gun that a thug found. Or planted to help himself. Whereas the state's argument will be something close to what you proposed in your post. Overall, I think finding the gun would help the state, for the reasons you mentioned, even without conclusive ballistics. (So long as the caliber is the same.)
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As far as the "showing he's a serial killer" thing - unless the deaths are related by some kind of common plan or occurrence, you don't try all of them together. Each trial is separate, and you can't refer to any other pending charges.
In each trial the state could try to introduce evidence of the other deaths insofar as that evidence goes to "motive, opportunity, intent, preparation, plan, knowledge, identity, or absence of mistake or accident." Each state has its own standard. It's usually hard to introduce evidence showing other crimes under those exceptions. I'm not sure how the state would do it here, since the other murders/shootings are factually quite different from this one. The fact that a rental car was used wouldn't be enough to tie them together.