It was day three of the Casey Anthony murder trial and Casey's dad George Anthony was back on the stand.

For three days, he has been sitting in the courtroom while his daughter accuses him of horrific sexual abuse.

A witness testified Thursday that Casey said, "Oh my God, I'm such a good liar."

Is abuse the reason she lies .. or is she doing the lowest of the low ... blaming her dad for the death of her daughter to save herself.

Could George really have been a part of some elaborate cover up? Dr. Drew and his guests take a closer look.