Attorneys in federal cases stemming from crimes on American Indian reservations have new guidance on what's needed to prove a defendant is Indian.

Federal authorities have jurisdiction over major crimes on tribal land when the victim, suspect or both are American Indian. A two-part test determines who is Indian.

The 9th U.S. Circuit Court of Appeals revised the first part of that test in an opinion Tuesday — no longer requiring that the degree of Indian blood be traced to a federally recognized tribe — and restored an Arizona man's 90-year sentence on assault and firearms charges.

The court said evidence at trial was enough to find Damien Zepeda is American Indian. Zepeda, an enrolled member of the Gila River Indian Community, disagreed.

"That's why it was so important to clarify that the proof in this case was sufficient," said Arthur Hellman, a University of Pittsburgh law professor who monitors the 9th Circuit. "This will lay down the rule for future prosecutors."

In 2013, a three-judge panel of the 9th Circuit ruled prosecutors did not prove beyond a reasonable doubt that Zepeda's bloodline of one-quarter Pima and one-quarter Tohono O'odham derived from an American Indian tribe recognized by the U.S. Bureau of Indian Affairs. It reversed all but one of nine convictions and ordered a lower court to resentence him.