Under the legal codes of Texas, the cop does not have a leg to stand on. https://statutes.capitol.texas.gov/SOTWDocs/PE/htm/PE.9.htm
Basically what that means is that in a particular situation I might not accept the validity of a certain law,as it's applied in *that* case,and as a result I,as a juror, might reject instructions that the judge might give to me during,or at the end of,the trial.
In *this* case I'm inclined to believe that if the kid's account is accurate then the cop just might have been justified,morally if not legally,to fire.
This woman absolutely should not be dead. I think it's far more likely than not the cop handled this case...the approach to the house for example...badly.If so then he could certainly be accused of serious negligence.
Again,assuming that the kid's account is accurate,I could see the cop deserving time in prison for major negligence...but I don't see anything close to "murder" as *I* define the word..
And,quite frankly,I wouldn't care what Texas law might say.