An American couple convicted and later cleared of wrongdoing in the death of their adopted African-born daughter in Qatar returned to Los Angeles on Thursday afternoon, a family spokesman said on Twitter.Matthew and Grace Huang left the tiny Gulf Arab state on Wednesday after a ban on their travel issued by that government was lifted, ending a nearly two-year ordeal."Mission accomplished. Matt and Grace are in Los Angeles. They have not stopped smiling," spokesman Eric Volz said in a tweet posted about 3 p.m. PST.He later tweeted that the Huangs were "on their way to be reunited with their sons."A website created to publicize the case said the Huangs had moved to Qatar so that Matthew Huang, a Stanford-trained engineer, could work on a project related to the 2022 World Cup.The Huangs were arrested in January 2013 after an autopsy found their 8-year-old daughter, Gloria, died of dehydration and cachexia, an irreversible loss of body mass. The couple said Gloria suffered from malnutrition-related diseases since they adopted her from Ghana at age 4.