Chile needs the agency to defend its democratic institutions and prevent a repeat of the South American nation's painful history, Bachelet said.

The goal is to "promote a culture of peace and education about human rights principles in present and future generations," she said.

The new law gives the National Human Rights Institute the power to investigate and recommend charges in cases where human rights are violated. Once appointed by the president and Congress, its leaders can be removed only by the Supreme Court, giving the institute considerable independence.

"We hope the institute will be more than a mere symbol and that it will be able to seek truth, enforce justice and become a safeguard for human rights in the future," Lorena Pizarro, president of the Family Members of the Detained and Disappeared, told The Associated Press.

In addition, the institute also is authorized to look at cases from the 1973-90 dictatorship of Gen. Augusto Pinochet. According to an official tally, 3,197 people were killed by government agents for political reasons during that era. Of those, 1,192 were made to disappear, less than 8 percent of whom have been located or identified in 20 years of democracy.

Pizarro's group lobbied for the creation of a rights agency for years, although the institute falls short of what the group wanted.

Family members of slaying victims during Pinochet's reign will be able to present cases and ask the agency to file charges against those they think were responsible. But this process excludes the estimated 28,000 people who survived being tortured.

The agency will also be given six months to build on the work of an earlier government-sponsored effort to investigate crimes of the dictatorship, enabling more victims to come forward with evidence they were imprisoned or tortured. But the law doesn't address whether torturers can be publicly identified, another sore point for the victims' families.