Casey Anthony: Letters Could Be Her Demise, Says Ex-Prosecutor Robin Sax

LOS ANGELES (CBS) As a felony prosecutor for over 15 years, I've seen how jurors in our instant-information world want and expect a reason, a motive - to understand why a crime occurred and how it occurred - although this is not legally required to prove a case.

PICTURES: Missing Caylee

In the case of Casey Anthony's alleged murder of her child Caylee, the jury will want to know how a mom, an attractive "normal" woman, could do such a thing to her own daughter.

Luckily for the Orange County, Fla., prosecutors, with an onslaught of Casey Anthony's jailhouse letters plus hours of taped jailhouse interview transcripts, they can know. The release of the letters not only gives us a sneak peak into her mind, but also begins to set the stage for the drama that will unfold once this case gets in front of twelve jurors.

And drama it will be!

Some of the disclosures are terrific for the prosecution; for instance, the claim that she would sometimes use drugs including chloroform to get her daughter to sleep. Chloroform could be a key piece of the prosecution's case.

Not all of the letters and transcripts are as helpful for the prosecution though. In some cases, Anthony alleges that she suffered sexual abuse by her brother, which may evoke sympathy for the defense.

But, as a prosecutor, you sometimes roll the dice by bringing these kinds of revelations into the mix. Bringing out the corroboration of something as important as the use of chloroform by Anthony is much more helpful than the potential sympathy factor that the alleged sexual abuse may bring.

This will be a case of stories. We already are clued into the prosecutor's story. If you have forgotten the major pieces of evidence, here are the highlights listed:

1. Defendant being caught in numerous lies about material facts;

2. Friends saying the defendant had a history and a reputation for lying;

3. Defendant's mom, Cindy Anthony, calling 9-1-1 saying that she had not seen Caylee for weeks (Casey didn't even report her own daughter missing!);

4. Defendant's dad, George Anthony, a former police officer, smelling and reporting an odor that was unmistakably that of a dead body in his daughter's car (although George Anthony does not stand by that statement);

5. Defendant stealing money from her friend and also apparently from her own parents which shows callousness and is indicative of her moral turpitude;

6.Chloroform searches turning up on Anthony's computer (Ring a bell? Recall Scott Peterson's trial where his computer showed searches for tide patterns in the water where his wife was found murdered);

7. Caylee being found less than a mile from the Anthony home;

8. Pictures EVERYWHERE showing Casey partying it up, even after Caylee was "missing";

9. Journal entries suggesting that Casey had never been happier around the time that Caylee went missing;

10. Caylee's body being discovered in a bag that also contained a Winnie the Pooh blanket that was missing from Caylee's bed;

11. Duct tape being found on Caylee's remains with apparently deliberately placed heart sticker residue on duct tape right where Caylee's mouth was;

12. DNA turning up in Anthony's car consistent with decomposition along with traces of chloroform;

And perhaps the most damning evidence against Casey -- the reason, the answer to "why" she might murder her own daughter, the smoking motive: she didn't want to be a mother anymore.

Anthony wanted to party and be free, and so researched a murder method (chloroform) and went ahead and got rid of her daughter (one mile from their home)... Sounds like an awful scenario. But it may very well be true.

That Casey Anthony is a party girl who killed little Caylee in favor of a liberating, carefree life is not a new theory. But these letters and inmate interviews now support the idea that she was too young to have a kid and could not hang with being a mom, wanting freedom from everything, and being willing to do absolutely anything to get it - including murdering her 2-year-old baby.

We can expect that defense attorney Jose Baez and his team will try to discredit the letters and jailhouse talk as not reliable information (i.e. obtained from snitches who simply wanted a better deal in their own cases). But how many bullets can Baez dodge? How many coinky-dinks can he possibly claim? How many other people can he point fingers at? Ladies and Gentleman, I believe the People rest and can prove their case beyond a reasonable doubt. Mark my words!