there is a counter sniper device called boomerang , it works on a series of microphones and compares the sound from one vs another
it is rather amazing how fast it can call out direction and angle pointing a spotter or sniper to the location of the shooter in an urban environment.
unless they are supplying USMC sniper teams to go with it i don't see how it will reduce crime in the short term I do see how it could be coupled with video surveillance to bring about much faster investigations and convictions.
if you arrived on scene and already know where the shot was fired from where to look for casings where to dig the bullet out of the wall , import the data into a crime scene emulator with a few pictures and create a virtual 3d image of a crime scene showing the frame by frame, juries would love it.
so if by gaining a greater rate of conviction they plan to lower these crimes maybe.
next problem is going to be , since the system was intended for super sonic projectiles , can it be calibrated for sub sonic shots potentially muffled by wrapping a old t shirt around the gun before firing or jabbing it into the victims ribs first and how many false positives will there be will fire crackers set it off.