An American Christian couple could be handed the death penalty for allegedly starving their daughter to death last year.

Matthew and Grace Huang's 8-year-old adopted daughter Gloria died in their home in January 2013. The Qatari government have accused the parents, who are ethnically Asian, of killing Grace to harvest her organs.

Campaigners believe they have been wrongly accused due to suspicion regarding their bi-racial family, which is unusual in Qatar.

Gloria and her two brothers were originally adopted from Africa. The family moved to Qatar from LA for Matthew's work as an engineer in 2012, and insist that Gloria suffered from an eating disorder which is attributed to her being born into extreme poverty in Ghana.

According to a website campaigning for the Huangs' release, "From time to time she [Gloria] would exhibit an eating disorder – common among children with backgrounds similar to hers – where she would refuse food for days at a time and then eat more than an adult. Other times she would eat food from the garbage even when she had healthy food available. Yet most of the time she was vibrant and seemingly healthy. She then died suddenly in the midst of one of her cycles of refusing to eat."

Following her death, the Huangs were charged with murder and sentenced to three years in jail. They served 11 months in an Islamic prison before being granted bail last November. Now under house arrest and are not permitted to leave Qatar, a hearing is due to take place on November 30 during which they could be given the death penalty.

There is no physical evidence that Gloria suffered any starvation, and independent witnesses testifying in court that they had seen her eating several days before her death.

The medical examiner who conducted the autopsy also told the court that he had never mentioned the word "starvation" in his reports, but instead "emaciation".

Campaigners insist the Huangs are innocent, and that their continued detention is a gross violation of international human rights.

"The Qatari police were fully justified in investigating Gloria's death. But facts refute the charge that the Huangs starved their daughter or that they had adopted her for illegitimate reasons. The continued detention of American citizens Matthew and Grace Huang should end and they should be allowed to travel home to the United States immediately," a statement on the website reads.

Prayer vigils are being held by the Huangs' home church, Lake Avenue Church in Pasadena, California, ahead of their next hearing.

In a letter to the church around Easter 2013, Matthew wrote: "The power of Jesus' work on the cross gives us new life. I am reminded that Easter is a time for rebirth, renewal, and restoration.

"My family needs to be restored together. My emotions are tired and weary. Jesus brings restoration, and we are reminded of that this Easter."

A statement from the US State Department in October calls on the Qatari government to allow the Huangs to travel back to the US, where their two sons are currently living, pending the completion of their trial.