Disturbing details in 'Baby Grace' trial

The little girl was known as "/*Baby Grace*/" until her remains were identified. A fisherman found the remains in a plastic container in Galveston Bay in October 2007. We would eventually learn that Sawyers had died months earlier in July at her family's home in Spring. Her mother and stepfather are charged with killing her.

The first day of trial was filled with graphic testimony. Several jurors broke down in tears when they heard details of how the little girl died.

Trenor sat quietly, sobbing a few times as her videotaped statement was played for the jury. It's a statement that described in graphic detail the day her little daughter died in her arms. At one point, she described how Sawyers told her mother, 'I love you,' even as the beatings continued.

Trenor and her husband, Royce Zeigler, are both accused of killing Riley during a disciplinary session in 2007. Trenor described on tape how her husband took the day off to show her how to discipline Sawyers, saying that Zeigler told her, "We had to break her in."

Trenor described how the beating began, first with a belt, then a thicker belt and how it led to putting her head under water.

"I found myself doing that because he was there and that's what he was doing," said Trenor in the videotaped statement.

Trenor claims Ziegler threw Riley onto the floor and a wall, striking her head. She claims she wanted to call 911, but Ziegler warned her they would go to jail.

"Was it unacceptable?" Trenor's attorney asked jurors. "Yes, but it was not capital murder."

Trenor went on to describe how Ziegler allegedly used bleach to get rid of evidence. Prosecutors say the couple then stuffed the little girl's body into plastic bags and then a plastic container.

Assistant District Attorney Kayla Allen said Trenor simply, "...watches her float under the causeway."

The jury listened to that videotaped statement before going home for the day Tuesday.

Trenor faces up to live in prison without parole if she is convicted. Her attorney advised the jury that they could convict her on a lesser charge.

Trenor's husband, Royce Zeigler, awaits his own trial on capital murder charges. As in Trenor's case, prosecutors are not seeking the death penalty. Instead, they're asking for life in prison without the possibility of parole.

Trenor gave birth last June while she was behind bars awaiting trial. The baby boy was placed in the custody of Trenor's aunt and uncle in Dallas. Trenor relinquished her parental rights. Zeigler has not.

More details from ABC13's Gene Apodaca, who was in the courtroom Tuesday

Kimberly Trenor sat quiet for most of the trial Tuesday. The only time we actually heard her voice was when Galveston County district Judge David Garner asked her how she pleaded to the charges. She replied with an emphatic, "Not guilty."

The mood of the courtroom was somber as opening statements began. Prosecutor Kayla Allen laid out the case in graphic details, describing how she says Trenor and husband, Royce Zeigler, killed little Riley Ann Sawyers, then tried to cover up the crime by dumping Riley's body into the Galveston Bay.

Trenor's attorney described Trenor as a young mother who had been through difficult relationships in her life.

The first witness was Galveston County Sheriff's Detective Michael Barry. He described how he was one of the first to respond to reports of remains of child in Galveston Bay. The unknown child was given the name "Baby Grace." He described how Riley's grandmother identified the remains after seeing a sketch of the child.

The tears came when prosecutors played a videotaped statement of Trenor explaining what happened the day Riley died. Trenor teared up in court as the statement was played. The graphic details contained in the statement also brought tears from at least two jurors. The statement was four hours with Trenor describing the act as well as how she claims she and Zeigler discarded the body. The first day of testimony wrapped up just after 4:30pm Tuesday. The jury will return tomorrow to hear more testimony. If convicted of capital murder, Trenor faces up to life in prison without the possibility of parole.