I will reiterate to you classy the law in Michigan. The doors do not have to have been forcibly unlocked to present to the homeowner a reasonable assumption McBride was attempting to gain unlawful entry into the home. The fact that the screen door is locked, of which I didn't actually see that in the police report so it is not a confirmed fact that I know of at this point, does not matter when it comes to the legal statute.
It is very hard to prosecute someone is using castle doctrine laws as an affirmative defense to defend their home. It doesn't require physical evidence of someone attempting to forcefully trying to enter a home for a homeowner to defend themselves by using lethal force. All it takes is a reasonable assumption by the homeowner that someone is trying to gain unlawful entry into their home.
Now, to break down that part, we have to go with what we know as facts that may or may not allow that reasonable assumption. Obviously signs of forcible entry WOULD be direct physical evidence that would allow anyone to reasonably assume that someone is trying to gain unlawful entry.
But there seems to be a lack of that evidence, as least shown to us by the media, of what could be positively construed as forceful entry. There is circumstantial evidence that may be construed, such as the screen being popped inward, but we don't know at this time if that was like that when McBride showed up or if she did that.
Since McBride is dead, there are no witnesses to the shooting that I am aware of, and there are no surveillance videos, the majority of evidence is going to come from the homeowner. Which is WHY it is hard to prosecute these kinds of cases. If the homeowner swears that McBride was shaking the door, slamming on it, screaming epitaphs at him to open the door, or anything along those lines then basically there is zero case without evidence to contradict those claims. Because all those actions claimed by the homeowner would be enough to allow for reasonable presumption that McBride was attempting to gain unlawful entry.
There is also enough circumstantial evidence to back up any of those claims, had they been made by the homeowner. These are in regards to McBride's drug addled mental state at the time. Someone on drugs and alcohol will not always react rationally and may have done things, such as trying to gain unlawful entry, that they would not normally do.
My bet is this though. In lieu of some hardcore physical evidence, this case is going to come down to what the homeowner actually stated to police. That is not to say that what he claims is the actions that McBride took. But the whole case, I believe, for the prosecution will rest on the statements made by the homeowner. Of which none of those statements have been made available to the public from the investigation.
Arguing over whether the screen door was locked or not doesn't really matter at this point. You, spidey, and spatiallyaware are just rilling yourselves up over out of place circumstantial evidence posted to the public by the media.