The San Pasqual Band of Mission Indians' efforts to expel about 80 of its members was thwarted last week by the federal government, which concluded that the Valley Center tribe did not provide enough evidence to justify removing members of the Alto family from its rolls.

In a letter to the tribal chairman, the U.S. Bureau of Indian Affairs said the descendants of Marcus R. Alto Sr., who died in 1988, should remain official members of the tribe.

The dispute, one of several rifts in recent years involving tribal membership, has split the tribe's governing council for months and threatened its ability to operate its casino, which opened in 2001.

Earlier this year, dozens of Alto family members were locked out of their casino jobs and denied their share of casino revenues. An official with the bureau said Monday the decision means Alto family members should get their benefits restored.

Angela Martinez-McNeal, an Alto family member and a spokeswoman for the family, could not be reached for comment on Monday.

The bureau's letter, dated Nov. 26, was in response to an enrollment challenge filed by tribal member Ron Mast last year. The challenge included a report prepared by an anthropologist hired by the 300-member tribe that concluded Alto was not the biological son of tribal members Jose and Maria Alto.

Mast, reached by phone in Ohio on Monday, said he had not seen the bureau's letter, but planned to continue his challenge.

"We have to go to court on this," Mast said. The evidence "shows they're not Indians."

Allen Lawson, the tribe's chairman, has declined to comment on the dispute and did not return a call for comment on Monday.

In recent months, rival factions of the tribe have held competing governing council meetings, each claiming to be the legitimate government.

In July, Jim Fletcher, superintendent of the Bureau of Indian Affairs for Southern California, sent a letter to San Pasqual officials warning them that the split threatened their casino because federal law prohibits them from operating casinos without a functioning government.

Citing the anthropologist report's findings, the tribe began its efforts to disenroll the Alto family members, including removing dozens of them from their jobs at the tribe's Valley View Casino in June, and suspending their share of monthly casino payments.

Tribal officials said in a letter to the bureau that the payments were being held in special accounts escrow until the matter was resolved.

On Monday, Fletcher said the Alto family members should be allowed back at their casino jobs.

"What this means is that all these folks are now considered members and that they may get their jobs back," Fletcher said.

If the tribe does not give tribal members their benefits, San Pasqual may be in violation of federal rules governing gambling, because casinos are supposed to benefit all tribal members.

Tribal membership disputes are troubling many Indian communities throughout the nation. Though questions about who belongs have festered for generations, the feuds have become increasingly bitter in recent years as tribes' casino wealth grows.

Since 2004, the Pechanga Band of Mission Indians, which owns a large hotel and casino complex near Temecula, has disenrolled about 240 members.

Factions within the Rincon Band of Mission Indians, which owns a hotel and casino near Valley Center, led a failed attempt to remove its former chairman, John Currier, and dozens of members of his extended family.

Most tribal governments make their own decisions over who belongs, often requiring strict family ties to the tribe. However, the San Pasqual tribe's constitution allows the Bureau of Indian Affairs to be the final arbiter of those disputes.

Last year, Mast filed his challenge saying that the Altos were descendants of Marcus R. Alto Sr., who he contends was adopted as a child by his aunt and uncle, Jose and Maria Alto, and wasn't their biological son.

The tribe's enrollment committee agreed with Mast's challenge and forwarded the anthropologist's report and its evidence to the bureau.

Among the evidence the tribe submitted to the bureau was a baptismal certificate, which the enrollment committee said proved Alto was not the son of Jose and Maria Alto. The certificate listed the name of the child as Roberto Marco Alto and listed Maria Barrios as the mother.

In its letter, the bureau said the certificate did not prove that Marcus R. Alto Sr. was the child named in the certificate. And even if he was, it suggested that Alto was the son of Jose Alto, who was listed as the father in the certificate, making him and his descendants eligible for membership in the tribe.

"Assuming that this baptism record is Mr. Alto's, this would prove that he is the son of Jose Alto," according to the letter, which was signed by Dale Morris, the bureau's regional director in Sacramento.

In the letter, Morris added that San Pasqual may choose to amend its constitution to remove the bureau from its membership process in the future.

Contact staff writer Edward Sifuentes at (760) 740-3511 or esifuentes@nctimes.com.