While Dateline does indeed do that, Saber, in this case, I don't think this is Dateline leaving things out. I just did a quick Google search of "Jean Tan." Just her name. Charlie's name appeared in the headline of every article that the search spit back, and I think that's the point that his defense team in the first trial and even the judge in the first trial was trying to make.
The defense team explicitly brought up Mom and the judge in the first trial said that the prosecution did not show evidence that Charlie committed the murder. Loading the gun is not the same thing as committing the murder. Theoretically, while odd, Charlie could have loaded the gun for his mother each time, and his mother could have done the shooting. Odd, yes, but they waited four days to report the crime, so odd's already in play.
Participation by Charlie is obvious, but participation by Mom is also obvious by virtue of the Mom's 911 call. The cops didn't believe Charlie's story and started digging, but they believed Mom's story? The unequal levels of discussion are glaring, and considering that the prosecution had to work to file the gun charges, the lack of effort to dig into the story of another person who was also in that house is also glaring.