Shemeeka Davis, 41, was sentenced to 25 years to life in prison for the torture and murder of 15-year-old Jazzmin Davis and to life in prison with the possibility of parole for the torture of her twin brother, who survived years of abuse.
Davis, the aunt of Jazzmin and her brother, wept loudly throughout today's hearing and as the sentence was handed down.
"I'd like to say that I'm very sorry," she said between sobs. "This was never my intention ... and I wish I could change everything."
On Sept. 2, 2008, Jazzmin's naked, gaunt and scarred body was found on the floor inside the Antioch home where for years, the only mother she had known abused her and her brother.
Police said that when she died, the teen was 5 foot 7 feet tall and weighed about 78 pounds.
A coroner's report found that she died from a combination of repeated physical abuse and malnutrition, Deputy District Attorney Satish Jallepalli said.
Jazzmin's twin brother was also found to be scarred and severely malnourished, but survived and testified during Davis' trial last summer.
At the end of the trial last June, a jury convicted Davis of first-degree murder, torture and felony child abuse charges and found her legally sane at the time she committed the crimes, despite her dual plea of not guilty and not guilty by reason of insanity.
Defense attorney Betty Barker argued throughout the trial that Davis suffers from severe mental illnesses, including psychotic delusions, which prevented her from forming the intent to torture the twins.
Jallepalli agreed that Davis is mentally ill, but argued that she chose to keep hurting the children and covered up the abuse because she knew it was wrong -- skipping the twins' doctor's appointments and keeping them home from school.
She had taken custody of the twins - who were born to a crack-addicted mother - shortly after they were born, raising them in addition to her three biological children.
A week before Jazzmin died, Davis was granted legal guardianship of the twins.
But Jallepalli said during Davis' trial that there was a clear difference in how she treated her niece and nephew.
The twins were not allowed to eat with her biological children and were not given the same food, if any at all, he said.
Davis would also lock the pair in a closet for long periods of time, forcing them to urinate and defecate on the floor.
When the twins were about 9 years old, Davis began beating them with belts.
Jallepalli said during the trial that over the years, Davis used electrical cords, a wooden rod and a belt with an attached padlock to beat the children and sometimes burned them with an iron.
As the beatings escalated, Davis stopped taking her nephew to doctor appointments to be treated for sickle cell anemia. In the year before Jazzmin's death, she also kept the teen home from school and even kept her from leaving the house, Jallepalli said.
Social workers who monitored the twins' care throughout their lives never noticed or reported the abuse, attorneys said.
The San Francisco Human Services Agency, which was in charge of overseeing the twins' care, agreed last year to a $4 million settlement with Jazzmin's brother.
The Antioch Unified School District agreed to settle with the teen for $750,000 and has implemented changes to its attendance policy.
Before handing down the sentence in Contra Costa County Superior Court today, Judge Susanne Fenstermache heard emotional statements from several of Davis' family members, who requested leniency.
"I've known her all my life, and I know that she's not a monster ... we will continue to pray for her and support her," said one man, Davis' cousin.
Jallepalli read two letters from other family members of the twins addressed to the court, including an aunt who wrote, "I can't begin to imagine how my niece felt during that last attack ... please have no mercy for sentencing."
The prosecutor also read entries from Jazzmin's journal in the months leading up to her death in which she wrote how much she loved her foster mother and wanted to make her happy.
In a later entry, Jazzmin described being "in big trouble" for failing to clean the bathroom.
"I'm going to lose all my privileges and end up in the same position I started in ... I'm so confused ... someone help," she wrote. Before handing down the sentence, the judge told Davis that she didn't consider her a monster.
"This is a sad day for everyone," Fenstermache said. "I know you wish you could undo this ... but it's been done."
Davis will be 69 years old when she becomes eligible for parole, attorneys said.