The tragic case in New Zealand that led to them putting all PCPs on ticket was a police officer investigating a drugs case, calling upon a suspect, and being hit once in the chest by a pellet from a 22 FX Monsoon.
The Monsoon is easily capable of 30fpe and at the time, the NZ laws didn't prohibit or licence any airguns regardless of power.
The officer was killed by a single shot (from a semi auto).
From this we can deduce, in the cold light of day:
1. It was a single shot, so having been fired from a semi auto is irrelevant.
2. The rifle was freely available without a licence.
3. It was probably running around 30fpe; the journalists at the time described it as "high power".
4. It wasn't a drive-by scenario.
However it is held up by some commentators as a reason why there should be special concern about the availability of semi auto.