WASHINGTON - Arizona experts said the Supreme Court's recent ruling against a Native American father who was fighting to stop his daughter from being adopted may only have "muddied the waters" for future cases.

"We're a little disappointed" in the court's ruling in Adoptive Couple v. Baby Girl, said Arizona Assistant Attorney General Dawn Williams.

The court ruled 5-4 last week that the Indian Child Welfare Act does not guarantee a biological father's parental rights to a child after he has relinquished his role as her caretaker.

The 1978 act was passed in the face of an alarming number of unlawful removals and adoptions of Indian children by non-Indian parents and foster care programs.

The ruling "will raise some ambiguities on how to interpret the case" of adoptive placement preferences, said Barbara Atwood, a University of Arizona law professor and co-author of an American Civil Liberties Union brief in support of the father.

But the American Academy of Adoption Attorneys, one of the groups that sided with the adoptive couple in the case, disagreed. It said in a statement that it thinks the ruling actually helps clarify adoption law. The high court's decision will "end some of the confusion created by inconsistent state court rulings and laws," the attorneys group said.

The case involved Dusten Brown, a Cherokee father, his non-Indian girlfriend and their daughter, Veronica, the "Baby Girl" in the adoption fight, who is now 3.

Brown did not pay child support and did not physically live with the girl after she was born. Court records say he relinquished his parental rights in a text message to his estranged girlfriend and signed a form consenting to the child's adoption by a South Carolina couple, who had been present for the girl's birth.

But when the couple sent final notification of the adoption, Brown sued to keep custody.

Justice Samuel Alito wrote for the court that while the Indian Child Welfare Act was meant to prevent the unlawful "removal" of Indian children from tribal lands, it did not necessarily prohibit "transfer of the child to a non-Indian parent."

Noting Brown's absence from his daughter's life before the adoption, Alito said the act did not prevent South Carolina courts from placing the baby girl in the custody of the adoptive parents.