The serious case review said Child BO5's parents "had been involved in a long-standing relationship punctuated by significant periods of instability, marital violence and alcohol misuse, particularly latterly by mother".

BBC: Doncaster children: Who are they?

The Capobiancos think the issue should be about whether the ICWA law can improperly block adoption proceedings voluntarily initiated by a non-Indian mother who had sole custody of her child, due to what the adoptive parents say is the Indian father's failure to establish a legal parent-child relationship under state law.

CNN: High court to tackle Native American adoption dispute