JACKSONVILLE, Fla. -- Some key evidence was presented for the first time in the trial of a mother charged with murder.

Amanda Butler was accused of inducing the seizure that killed her 2-year-old daughter in 2002.

Butler has served time in West Virginia for committing a similar crime against her son.

Prosecutors said the video will become a key piece of their case.

The video is grainy and in many ways hard to decipher, but investigators said it's a key piece of evidence in the case against Butler.

Detectives said the video shows Butler with another child, Ryley, secretly recorded in a West Virginia hospital about 20 months after Cheyenne's death. Doctors there were suspicious because Butler's newborn son was showing some of the same symptoms as Cheyenne.

In the video, Butler is seen holding her son Ryley, and police said at several points she covers the child's mouth, once with her hand and then a few minutes later using a cloth. And in each instance, they said, she is keeping watch on the hospital room door.

Butler has said she was using the cloth in her hand to wipe crust off the boy's mouth. But police and prosecutors said it was something more diabolical.

Butler pleaded no contest to child abuse and served a year in jail in West Virginia.

The police report said during that time, she told one inmate "she was doing the same thing to Cheyenne as she did to Ryley."

A second inmate said Butler told her "on one occasion, it went a bit too far with Cheyenne."

And Butler told her she smothered Cheyenne to get her husband back home because she missed him.

Butler also said, "It was an accident. It didn't mean to happen."

Finally, Butler told the inmate that her children have Munchausen's, a syndrome in which the affected person exaggerates or creates symptoms of illness to gain attention and sympathy.

Immediately after her release in West Virginia in April 2006, Butler was arrested by JSO detectives to face murder charges.

Detectives said among the people they interviewed were Butler's neighbors and friends, some of who left their children in Butler's care.

One of them told detectives something else that could sway a jury.

In another supplemental report, he said that while Butler was baby-sitting their son, he had a seizure.

He found his son lying in a crib "stiff as a board and looking terrified."

And, he said, the child had no problems, until they once again allowed Butler to baby-sit.

Then there's the video. A lower court judge agreed with the defense and threw it out, saying it violated her privacy rights.

But an appeals court disagreed, and now the tape and documents will be part of the state's case against her.