Hamid Kamara was born in Sierra Leone in 1981. In 1990, his parents divorced in Texas.  Because Kamara was still residing in Sierra Leone, the state court did not order that one parent or the other receive custody of Kamara.  He later entered the United States as a visitor, and in 1994, he received his lawful permanent residence through his mother.  In 1998, when Kamara was 16 years old, his mother became a naturalized U.S. citizen.  Kamara was living with his mother at the time.  When Kamara applied to United States Citizenship and Immigration Services for proof that he had derived citizenship through his mother, his request was denied.  Kamara renewed this argument before the Immigration Judge, who found that he had not shown he was in his mother's "sole legal custody" at the time of her naturalization, and thus, could not establish his citizenship claim.  

On appeal, the Fifth Circuit determined that the derivative citizenship laws in force at the time of Kamara's 18th birthday only required him to show that he was in his mother's "actual uncontested custody," and not her "sole legal custody."  The "actual uncontested custody" standard was the correct one to apply when there is no judicial order regarding legal custody.  Because there was a factual dispute about whether Kamara lived in his mother's uncontested custody, the Fifth Circuit transferred the case to a District Court to adjudicate his citizenship claim.

The full text of Kamara v. Attorney General can be found here: http://www.ca5.uscourts.gov/opinions/pub/13/13-60807-CV0.pdf