HELENA, Mont. (AP) – An appeals court on Tuesday threw out the convictions of two Montana men with American Indian heritage after ruling their bloodlines and affiliations did not merit prosecution under the law that establishes federal jursidiction over serious crimes on tribal lands.

The men successfully appealed their convictions on the grounds that they were not American Indians for purposes of prosecution under the Major Crimes Act.

U.S. Attorney Michael W. Cotter said his office was reviewing the ruling to determine whether it would seek a retrial.

“Although we are disappointed with the results of the opinion in these cases, we welcome additional clarity in this gray area of the law,” he said in a statement.

The decision by a three-member panel of the 9th U.S. Circuit Court of Appeals addressed two cases that were appealed for the same reason.

Gordon R. Mann Jr. was charged in October 2008 with aggravated sexual abuse of a minor at his house on the Blackfeet Indian Reservation. Prosecutors filed charges under both the Major Crimes Act and the General Crimes Act, which provides federal jurisdiction over certain crimes committed on tribal lands when either the defendant or the victim, but not both, are American Indian.

Mann confessed, but moved for acquittal after the prosecution presented its case at trial arguing that he was a member of an Indian tribe that is not recognized by the federal government and should not have been charged under the Major Crimes Act.

U.S. District Judge Sam Haddon rejected that argument on the basis that American Indian status is a jury determination. The jury found that Mann was American Indian and found him guilty under the Major Crimes Act, but it did not consider the count under the General Crimes Act. Mann was sentenced to over 23 years in prison in February 2009.

The appeals court vacated Mann’s conviction because he is a member of the Little Shell Tribe of the Chippewa Cree, which is recognized by the state government but not by the federal government. It cited a 1993 ruling involving another Little Shell tribal member that said the purpose of requiring proof of Indian status was “not to identify individuals as Indian solely in a racial or anthropological sense, but to identify individuals who share a special relationship with the federal government.”

Mann’s attorney, Palmer Hoovestal of Helena, did not immediately return a phone call seeking comment.

In the second case, Shane Maggi was convicted of assault with a dangerous weapon and related firearms charges for a May 2007 attack on Kelly and Kimberly Hoyt in their home on the Blackfeet reservation. He, too, was charged under the Major Crimes Act, convicted and sentenced to 42 years in prison.

In his appeal, Maggi did not challenge that he pistol-whipped the Hoyts for allegedly stealing illegal drugs from him, but contended he is not an American Indian for purposes of prosecution.

The appeals court found that Maggi has very little Indian blood, is not an enrolled member of any tribe, is not eligible to be an enrolled member of any tribe and does not receive any tribal benefits.

“To the best of my knowledge, because the 9th Circuit found ... that Maggi should be acquitted, double jeopardy attached so there’s no opportunity for a retrial,” said Maggi’s attorney, Dan Donovan of Great Falls. “I believe he should be released, which is pretty significant for him.”

Donovan said he has not spoken with his client about the decision.