Personally, I believe that statement was made to serve an important police function, which is to prevent public panic from the idea that someone is roaming around, breaking into homes and murdering the inhabitants. I've noticed LE usually make some kind of statement shartly after a crime like this, to the effect: public should exercise caution, or this appears to be targetted and the public is not at risk, etc.
In this case, in the first hours they were unsure what had happened, but what they said was true, as that officer knew it at that moment..
When police inform the public of the state of an investigation, they don't send a junior officer out to chat with random reporters. They hold an official press conference where the head of the investigation answers questions, because that's the person who knows the big picture.
I think reporters know this quite well, but the media is a competitive business, and they're chasing clicks.