What would Anthony have used to entice a witness? She is broke, her lawyer received less than $100K for the entire case, and she is universally loathed.
The state had a complete full court press of media and an unlimited budget and still couldn't tie her to the death, they couldn't even show a cause of death.
Casey Anthony probably killed her daughter or at least was involved, however we do not convict on probably. She was judged Not Guilty by a jury of her peers. Not Guilty is not the same as proved innocent. Our system worked precisely how it is supposed to work.