Well, because you’re going to hear about it one way or another, and the people making these decisions (about releasing information) have no right answer. Somehow, the information will get out; if the pigs say nothing, they’ll be accused of covering it up. So they try to get in front of the news and control what they can.
I don’t know why we’re this way, why the news organizations compete to be first to report on something, even with almost no information.
However: unless it turns out that the cops showed up and she started blasting at them, there’s no justification for you to be murdered just because you called for help. Whether or not you jump-scared a cop; whether or not you have dementia and a kitchen knife, or a baseball bat. Heck even if she had a gun. Pigs have training, backup, bullet-proof vests; these victims have fear, adrenalin, often mental health issues, and an expectation that the people they call for help aren’t going to show up and murder them.