The father of Casey Anthony said in a TV interview that aired on Wednesday he believes his daughter or someone with her drugged his 2-year-old granddaughter and caused the girl's death.

Casey Anthony was acquitted in July at a trial in Florida of a charge that she murdered her daughter, Caylee, in a case that drew nationwide attention after Casey Anthony reported the toddler missing in 2008.

Caylee's body was later discovered just outside of Orlando, Florida, in the woods less than a mile from the home of Anthony's parents, George and Cindy.

Prosecutors at trial argued that Casey Anthony, 25, killed the girl by smothering her with duct tape and later buried her to hide the body, but defense attorneys suggested that Caylee died from an accidental drowning in a backyard swimming pool.

Despite her acquittal, Casey Anthony has been scorned by the public, and her parents -- who at times have defended her -- have not fared much better in popular opinion.

In an exclusive two-part interview with TV psychologist Dr. Phil McGraw, Casey Anthony's mother, Cindy, said she believes the death was due to drowning, but her husband offered a different explanation.

I believe that Casey or someone else that she was with, possibly gave too much to Caylee, she fell asleep and didn't wake up. That's what I feel, George Anthony said on the Dr. Phil show, in an episode that aired on Wednesday.

McGraw asked George Anthony to elaborate on what substance he thinks could have been given to Caylee. George Anthony responded that it could have been a drug, such as the anti-anxiety medicine Xanax. He also mentioned chloroform, but seemed to discount that possibility.

George Anthony then, in response to a question from McGraw, explained what his daughter's motivation could have been for seeing her daughter drugged and sedated.

To go out and have a good time, to be with friends, to have this life that she didn't have with Caylee, George Anthony told McGraw.

The explanation from George Anthony, who also said that the pain of losing his granddaughter nearly pushed him to suicide, is similar to the view of some outside commentators on what may have happened to Caylee Anthony.

But Cindy Anthony expressed shock at her husband's explanation, and said on Dr. Phil that it was the first time she had heard that out of his mouth.

The mother of Casey Anthony also said that, even though she believes her daughter had something to do with Caylee's secret burial, she took her daughter's acquittal as a sign from God that Caylee's death was an accident.

I believe that justice for Caylee was when her mother walked. I believe that in all my heart, she said on the show.

Casey Anthony was found guilty of misdemeanor charges of lying to detectives during the investigation, after a jury acquitted her of a murder charge in the death of Caylee.

The first part of McGraw's interview with Cindy and George Anthony aired on Dr. Phil on Tuesday.