Some of the details of what happened the day Charles died were discussed on the Gray Hughes podcast where he interviewed Kay (Charles sister) and her husband. Kay was honest in saying that because the investigation into her brothers death is ongoing that there were various issues that could not be discussed.
But in that interview she did give a brief explanation of what she believed happened.
I would suggest checking out the podcast directly if you are interested as there was a lot of other information in the podcast about Charles, JJ and the Charles/Lori relationship that IMO was quite helpful in terms of understanding the overall situation.
Here is a link to the interview done by Gray Hughes on his youtube channel: