(CNN) -- A woman accused of killing her 2-year-old daughter and dumping her body in Texas' Galveston Bay went on trial Tuesday on capital murder charges in the child's death, court officials said.
Kimberly Dawn Trenor has pleaded guilty to an evidence-tampering charge, her attorney says.
Kimberly Dawn Trenor, 20, pleaded guilty last week to tampering with evidence in the case, but she pleaded not guilty to the capital murder charge, said her attorney, Tom Stickler.
Trenor's husband, Royce Clyde Zeigler II, 25, also faces capital murder and evidence-tampering charges, but is being tried separately and has not been arraigned.
The body of Trenor's daughter, Riley Ann Sawyers, was found in October 2007 in a large plastic blue container on an uninhabited island in Galveston Bay.
Jurors in Trenor's trial also will determine her sentence on the evidence-tampering charge, which carries a penalty of two to 20 years in prison, according to The Houston Chronicle.
Riley Ann's case drew national attention after a fisherman found her body. Authorities were unsure of her identity, and police dubbed her "Baby Grace."
After authorities distributed composite sketches of the girl nationwide, Sheryl Sawyers, the girl's paternal grandmother, contacted police from her Ohio home to say the drawing resembled her granddaughter. DNA testing confirmed the child's identity.
According to an affidavit, Trenor told police Riley had been beaten and thrown across a room and that her head was held under water before she died on July 24, 2007. She said the couple hid the girl's body in a storage shed for one to two months before they put it in the plastic container and dumped it into the bay.
The disposal of the girl's body led to the evidence-tampering charge. A medical examiner said Riley's skull was fractured in three places, injuries that would have been fatal.
A capital murder charge carries a mandatory sentence of life in prison, the Chronicle reported.
A cross has since been erected on the island where the toddler was found, which was named Riley's Island in her honor, according to the Houston newspaper.
Trenor and the girl moved to Texas from Ohio in May 2007 to be with Zeigler, whom Trenor had met on the Internet. While in custody, Trenor gave birth this summer to another child, who is now in the care of relatives, her attorney, Tom Stickler, said.