[HiTech RedNeck]

At best, this could be a hint that a bit of metal was found in the shot officer that they hope to match.

On the other hand, fishing expedition? As various bits of slugs and bullets get handed in, if it even looks slightly like it came from a now verboten gun, raids will follow on the homes of the very people that found them.

[R. Scott]

At best, this could be a hint that a bit of metal was found in the shot officer that they hope to match.

Possibly some residue, and it could be matched to a particular lot of ammo. There shouldn’t be a lot of spent rounds in a residential neighborhood. My problem would be in connecting the slug with wound - could it be a round fired from a suspect weapon and “found” by a concerned citizen?