Ft Worth police officer shoots woman to death inside her home

For the life of me, I don't understand why he didn't just walk up to the house and ring the door bell, if this was just a welfare check? At the very least, announce himself.

I mean, the door was open. Had he rung the doorbell or knocked on the screen door, one of two things would have happened. He would have either head commotion and people running (i.e. thieves) or he would have seen lights come on and Atatiana would have turned on lights and walked to the door (obviously this). This is all so incredibly avoidable it's sickening.