ST. MICHAELS, Ariz. (AP) – Federal prosecutors declined 50 percent of cases from American Indian reservations over a 5-year period, and the figure is higher for sexual abuse cases, a report released Dec. 13 found.

U.S. attorneys resolved 9,000 of the 10,000 cases they received in fiscal years 2005-2009, declining to prosecute in half those cases, while prosecuting or administratively closing the others, according to a U.S. Government Accountability Office report.

The report came in response to congressional inquiries regarding the declination rates that federal justice officials say can be misleading. Violent crime devastates tribal communities at rates higher than the national average, and federal prosecution often is the only way to bring justice to victims of major crimes.

Tribes can prosecute only misdemeanor offenses.

The most frequent reason for declining cases was weak or insufficient admissible evidence, followed by no evidence of a federal crime, witness problems and a lack of evidence that a suspect had criminal intent.

H. Marshall Jarrett, director of the Department of Justices's executive office of U.S. attorneys, said he was hopeful the report would be used to help reduce crime on tribal lands. He said the declination rates are not an appropriate measure of all the ongoing efforts to improve public safety in Indian Country.

“Each case must be evaluated on the evidence available to the prosecutor,” he said in a letter responding to the findings. “Accordingly, it would not be appropriate to use the data contained in this report to promote any kind of prosecutorial quota system or incentives to prosecute a higher number of individuals.”

More than three-fourths of the 9,000 cases were classified as violent crime, with 24 percent nonviolent. Sexual abuse and assaults accounted for 55 percent of all cases, with a 67 percent and 46 percent declination rate, respectively.

U.S. attorneys in Arizona, South Dakota, New Mexico, Montana and North Dakota received 73 percent of all Indian Country criminal matters. Declination rates for individual districts varied from 22 percent in eastern Wisconsin to 72 percent in eastern Washington. Forty-three of the 94 districts had no cases out of Indian Country.

South Dakota U.S. Attorney Brendan Johnson, whose district's declination rate was 61 percent, said he's more inclined to ask law enforcement to send him every case off the reservations so that his office can make a determination on whether it can be prosecuted. That in turn could lead to a higher declination rate but could also result in more cases tried, he said.

“One thing that's important for us as prosecutors is not to get caught up in statistics,” said Johnson, who chairs a subcommittee that reports to the attorney general on American Indian issues. “We need to try to get as many cases as we can to reduce crime.”

FBI investigators referred more cases to U.S. attorneys than any other agency, with 5,500 cases – 46 percent of which were declined. U.S. Bureau of Indian Affairs offices referred 2,355 cases and had a higher declination rate at 63 percent.

Federal officials interviewed for the report said those figures might reflect differences in the two agency's policies in what they refer to federal prosecutors. The BIA refers all matters, while the FBI might not send cases that it believes lack sufficient evidence for federal prosecution, according to the report.

A spokesman for the National Congress of American Indians, which represents tribes nationwide, said the report's findings aren't surprising but demonstrate the importance of making the declination rates public to move forward with improving public safety in Indian Country.

“We now need to focus on going from paperwork to working with communities,” said Thom Wallace. “Those efforts are being made.”