Doha: A Qatari appeals court acquitted on Sunday a US couple charged with parental neglect leading to their daughter's death by suspected starvation, ending a nearly two-year legal ordeal for the Americans.

Matthew and Grace Huang were arrested in January 2013 after the death of their eight-year-old daughter Gloria, who had been adopted from an orphanage in Ghana.

The couple, who are of Asian descent, were initially accused of starving to death their child to sell her organs but were later jailed for three years for parental neglect.

On Sunday the appeals court ruled the couple were not guilty and said they were free to leave Qatar, based on witnesses' accounts that Gloria was "not neglected in leading a normal life".

"Grace and I want to go home and be reunited with our sons," said Matthew Huang, describing the judicial process in the Gulf state as "long and emotional".

"We have been unable to grieve our daughter's death but we want to thank the judge for today's decision," he told reporters outside the court.

"We're looking forward to returning to the US," he said.

The witnesses had testified that they saw Gloria eating one day before her death, the presiding judge said.

"This negates the charge that she was prevented from eating, a charge that the court of first instance used as a base for its initial ruling," the judge said.

A forensic pathologist told court last month that Gloria's corpse showed signs that she had not eaten for days.

"I found no signs of food in her stomach and the whole intestine, and I found no other reasons for death," said the expert Anees Mahmud.

But the Huangs have insisted that Gloria died of an eating disorder rooted in a troubled early childhood.

Social media campaign

The couple were released in November last year pending trial, but the court denied their request to leave the Gulf state to join their other two adopted children in the United States.

Both adoption and multiracial families are rare in Qatar, a conservative Arab emirate, and the family's supporters maintain Qatari authorities misunderstood the Huangs' situation.

The public prosecutor had pushed for the death penalty for the Huangs, who were initially accused of starving Gloria to sell her body parts.

Supporters of the Huangs had launched a campaign on social media to call for their freedom.

The "Free Matt and Grace" website says the daughter, who had been adopted from an orphanage in Ghana, died "suddenly" on January 15.

It says she had suffered from eating disorders which "likely were triggered by the extreme poverty she endured at an early age".

In addition to imprisonment, the lower court had ordered the couple to pay a fine of 15,000 riyals ($4,100) each and to be deported after serving their sentence.

Matthew Huang last month criticised the court as a "sham," insisting that the couple feels "kidnapped and trapped".

The Huangs moved to Qatar in 2012 for Matthew, an engineer, to work on infrastructure projects linked to the 2022 football World Cup.

Their supporters describe them as a loving family and say they have collected supporting testimony from people who knew them in Qatar, which authorities declined to accept.