Both Addington and Toulou agreed generally with the intent of the bills, with most concerns over the legislation appearing to stem from "technical issues," or details about how the initiatives would be executed.

The other bills before the U.S. Senate Committee on Indian Affairs seek to expand coordination among federal agencies responsible for improving public safety on tribal lands, and expand tribes' ability to prosecute non-Native Americans in sex assault cases and crimes against law enforcement and children.

U.S. federal law gives tribes only a narrow set of instances in which they can pursue prosecutions of people who aren't Native American, including when a woman is assaulted by someone she knows.

"Criminals are free to offend with impunity," said Lynn Malerba, who is chief of the Mohegan Tribe and testified Wednesday.

U.S. Sen. Steve Daines, R-Mont, introduced two bills Wednesday to deal with the crisis. The first bill requires a study of ways to improve reporting of missing Native Americans and a look at the effects of methamphetamine and other illegal drugs on violent crime in tribal communities. The bill’s title is the Finding and Investigating Native Disappearance, or FIND Act.