Because I cannot give a link although I have heard this many times, I will say that, IMO, eyewitness testimony is notoriously unreliable. I see no reason whatsoever for this woman, Jane, to lie. I think she is telling what she remembers as being true. She was truly traumatized by whatever she saw and likely will never get over it. This incident (I think it was a murder, but that's IMO) has affected many people, and not just GZ and his family and TM and his family. I can detect raw emotion even in posts on the internet, by people who never knew or saw any of the parties. And I, myself, can get upset by statements which do not agree with my point of view in this case, where I normally am an even tempered, not terribly emotional person. Some think the injuries were serious, some don't. Actually, I don't.
To me, the most frustrating part is that we will never know for sure what happened. It can't be tied up with a neat ribbon and put away with a conclusion satisfactory for everyone, maybe even no one.
But I do think that these eyewitnesses are telling the story exactly as they think it happened, although they might be mistaken.