King 5 News Carri Williams took the stand for the last time on Sept. 6.

A mother accused of starving her adopted daughter and leaving her outside in the cold was convicted of manslaughter and homicide by abuse in Washington state on Monday.

Carri Williams and her husband Larry Williams were accused in 2011 of causing their Ethiopian teenage daughter’s death.

Carri Williams has maintained her innocence throughout the trial, but was found guilty of homicide by abuse on Monday, a representative of the Skagit County Prosecutor's Office said.

Larry Williams was convicted of manslaughter, a lesser charge than his wife’s. The jury could not come to an agreement that he had committed homicide by abuse and the judge declared a mistrial, according to NBC affiliate KOMO.

“There was no theory and insufficient evidence of manslaughter in the first degree," Larry Williams’ lawyer, Rachel Forde told KOMO.

Reuters reported that the couple’s daughter, Hana, died of hypothermia in the family’s backyard. The young girl was adopted in 2008 and investigators told Reuters that the young girl's parents beat her, starved her and forced her to use an outhouse.

Both parents were also found guilty of assault of a child linked to the abuse of their 10-year-old son, also adopted from Ethiopia. According to Reuters, the family practiced disciplinary methods from the book “How to Train a Child.”

Defense lawyers had argued that questionable parenting practices did not necessarily mean a crime was committed, NBC affiliate KING reported.

The trial had been delayed several times because Hana’s age could not be confirmed due to a lack of Ethiopian documentation, according to KING.

She was thought to be 13, but her accurate age was important to the case because homicide by abuse charges can only be pressed if the victim is under 16 years old.

"It was a very sad, sad story," Skagit County Prosecuting Attorney Rich Weyrich told Reuters. "It was something that shouldn't have happened. Fortunately, we were able to prove the charges, so we were able to hold them accountable," he said.

Both parents will be sentenced next month and could face up to life in prison, reported Reuters. Defense attorneys told KOMO that both will appeal the verdict.

Reuters contributed to this report.