[xone]

Then there was a claim a weapon could be made to shoot ice which would melt after killing the victim leaving no trace. Never heard anymore about it.

And how would that work? It has to cause trauma to kill. If an ice bullet, the guy would die of a gunshot wound with no bullet for examination, but the cause of death wouldn't be in doubt, there would be a hole.

[sargon]

Then there was a claim a weapon could be made to shoot ice which would melt after killing the victim leaving no trace.

That idea is mentioned at the beginning of the 1975 movie "Three Days of the Condor" starring Robert Redford...