Would you be keeping some things to yourself? Almost certainly. All that media attention was necessary to try to get a search for Christina that was ongoing. However, imagine you do not have a perfect child. (Who does?) And you know what the world values? The world values victims that are purer, whiter, and possess good, solid middle class values. All the better to emphasize that the victim is a contrast to every standard media perpetrator people see on TV -- because good guys require bad guys to validate their goodness. You see it on every cop show on television. Maybe it is just the memories you have of your child from when she was little that you want to hold sacred. All those dreams and hopes. Suddenly, all is exposed. There you are, with people looking to you lead them and to give them information you may not even have and you only have one desire: To find your cherished child. Do you thank people, left and right, anyone who give you the slightest help or hope? You bet you do and you go on thanking people (even if you are sometimes a bit disappointed in them) because you want them to go on helping and you want them to understand and want them somehow -- although it is hardly possible -- to love your child as you do. You would want the answers that you need, even if the answers come from her possible killer. You would appeal to his decency, because that is all you have to move him. You would not care about your child's lifestyle choices as much as you would just care about your child. Your arms would feel so empty. You would beg anyone. You would appeal to anyone. You would thank anyone. And if the police had a pretty good suspect, then you would show them every deference, because at least they would be heading in the right direction. Answers! All that drug stuff? It would not matter so much. You want your child alive at any cost. And if you cannot have that, you at least want her body. And you want it over! However the requirements of the law may take a long time to fulfill before it is over, so what you would want, barring that, is justice.
A friend of mine, her daughter was murdered and there were two killers (now in prison with life without parole) and the defense attorney of one of them went after my friend on the witness stand, claiming she should have known about her daughter's lifestyle choices. In short, putting the victim and her family on trial to create some sort of bizarre smoke screen for the defendant.
To some extent, I have a concern about that when people keep bringing up the drugs. It is sleuthing and is not victim-bashing, I know, but it sure is stuff that the defense attorney will use to mitigate his client's responsibility for the his crime, isn't it?
In the end, drugs or not, EA had her in his trunk and the burden on the prosecution will be not to prove motive, but to prove the crime.