Wonder if this will then be used to fulfill the dream of shooting ice bullets which then melt inside the victim, leaving less evidence. If memory serves, I think the CIA explored this at some remote point in time.

Wouldn’t there still be evidence that some object penetrated the person and ripped them apart and caused them to bleed out?

Surely the CIA has untraceable ammo at their disposal already?

Well no, because these aren't just ice-- it's an ice composite.

Concrete's not strong enough to be used as a bullet either- you'd need something roughly the size of a shotgun slug. If you're going that big, you aren't going for subtle.

It's a mix of water and celulose, do it does not disapear completely.

Make a bolt and use crossbow

I believe they used a different frozen compound than water, but yes.

Mythbusters busted ice bullets. IIRC, the ice didn’t tolerate being shot out of a barrel and disintegrated.