A Washington couple could face decades in prison following their conviction in the death of a teenage girl they adopted from Ethiopia.
Larry Williams, of Sedro-Woolley, was found guilty of first-degree manslaughter on Monday in the death of his adopted daughter, Hana Williams, who died of malnutrition and hypothermia.
Hana's adoptive mother, Carri Williams, was found guilty of homicide by abuse as well as manslaughter.
A mistrial was declared on a homicide by abuse charge for Larry Williams.
Hana Williams' emaciated body was found in the backyard of her family's home in May 2011. The girl was believed to be 13 years old at the time of her death, according to The Associated Press, but her age became a central question in the trial because there was no documentation available on her birth in Ethiopia.
Tests conducted on Hana's teeth and bones gave varying estimates of her age, which was a significant fact in the case, because a homicide by abuse charge applies only if the victim is younger than 16 years old.
The Williamses were also convicted of assault on a child related to the abuse of a younger boy they'd adopted, also from Ethiopia, at the same time as Hana in 2008.
Skagit County Prosecuting Attorney Rich Weyrich told ABCNews.com the children were subjected to torture.
"The girl was forced to sleep in a closet, use an outhouse, eat cold and frozen vegetables and wet peanut butter sandwiches," he said. "It's a litany of things we believe qualify as torture."
Before her death, Hana had also lost a quarter of her body weight. According to Weyrich, the girl went from 108 to 78 pounds before she eventually died of hypothermia.
The couple will be sentenced in October, and according to Washington sentencing guidelines, Weyrich said they could face decades in prison.
Defense attorneys for the couple said they planned to appeal the verdict, according to ABC News' Seattle affiliate KOMO.
When Carri Williams testified in August, she told the jury her daughter had lost weight before her death and said she believes the girl "unintentionally killed herself," according to KOMO.
"I never treated my daughter like a dog," Williams said.