Key testimony in the CASEY ATHONY accused murder mom pretrial hearings as corrections officer  gives crucial deposition.

Orange County corrections officer, Sylvia Hernandez, is scheduled to give sworn testimony in the Anthony case after being fired for allowing Anthony to exchange secret letters with another inmate.

The letters, later released as evidence as the state earlier this year were between Anthony and fellow inmate Robyn Adams.

Contained within the messages were references made by Casey to a "Zenaida Gonzalez " whom Casey told authorities she believed was responsible for the kidnapping of you daughter Caylee

The corrections officer had said that the notes allegedly said  "there was no Zenaida" and "Zenaida didn’t do this"

Investigators also divulged that Adams told them that Anthony would give Caylee "stuff" to make her sleep.

When probing to see if she meant chloroform, Anthony told the former corrections officer  she woud give the child "antihistamines or something".

Anthony is currently incarcerated at the Orange County Jail in Florida charged with the murder of her daughter, Caylee. 

The trial is docketed to begin May 2011.