A very sad incident. We have highly trained Traffic Police Drivers in this country and fortunately these incidents are extremely rare. I feel extremely sorry for the officer concerned, who will have to give an account for his actions and if found guilty of any offences, they will be treated as any member of the public would.
I do, however, have concerns about those who drive everyday patrol cars. I once saw one come flying round a corner and almost hit a pedestrian on a Zebra Crossing. The crossing was very close to the Police Station, so they must have known it was there.