JMO: I agree these facts fit the murder statute, she murdered him under TX law. Her case comes down to arguing a justifiable murder. Since TX has the Castle Doctrine, and the Castle Doctrine would justify the murder under TX law if she were in her own home, this case comes down to whether the mistake of fact that she was in her own apartment is found reasonable to the jury.
Unfortunately the language for lesser charges in TX do not seem to fit the facts here.
This is the TX statute that shows the levels of culpability (mens rea/mental state/intent):
PENAL CODE CHAPTER 6. CULPABILITY GENERALLY
BBM
This is the TX homicide statute:
PENAL CODE CHAPTER 19. CRIMINAL HOMICIDE
I bolded the 4 levels of culpability. In TX, murder requires intentionally OR knowingly. Manslaughter requires recklessly. Criminally negligent homicide requires negligently.
AG killed Jean knowingly and intentionally IMO and I think that's hard to debate. As VAgirlatheart commented on above, juries tend to follow the letter of the law. This is because they have to fill out specific jury instruction forms provided by the Judge.
I don't practice law in TX and I don't practice criminal law. But in my civil practice, which includes wrongful death cases applying the same 4 stages of intent that apply in TX, the jury has to select the level of intent before moving on to the follow up questions. If jury instructions are like the ones I've seen in my practice, if the jury selects "intentionally/knowingly" in their verdict they will be shut off from the lesser charges. (As a simple example the jury instructions may state, "if you choose intentionally, go to page 4; if you choose negligently, go to page 6; etc., and not even allow the jury to get to the lesser charges)
As an aside, I genuinely hope I am wrong about this. It is definitely possible that TX case law shows manslaughter or criminally negligent homicide can be applied even to knowing/intentional killings. This is a really tough case and I do not envy that jury at all.
@gitana1 or any other posters with legal experience please chime in.