Physics has a few things to say about the legitimacy of that story….
Electrically powered… shoots ice… - using…? Electro-magical-acceleration?
Ice is a poor penetrator. It has a low mass and is a very rigid crystalline structure - it tends to shatter rather than penetrate. The small size claimed would give the 'gun' a very limited range, possibly even less than a few inches.
At this range, you may as well use a typical "air needle" injection system, which has been around for some time.
But when gunshot wounds to the back of the head with no powder residue are labeled suicides in this country… who needs secret crime weapons?