For 34 years now, federal legislation has required institutions that receive federal dollars to identify and return native remains and ceremonial objects to existing tribes.
But an ABC News investigation reveals progress has been slow.
"Anyone can imagine how they would feel if their relatives were being held in an institution and their bones were being pulled for radiocarbon testing. No one would want that," said Ray Halbritter, Oneida Indian Nation of New York.
Under new guidelines, institutions that fall under the federal law cannot display the sacred items without permission.
For more on ABC News' coverage of repatriation efforts across the country, tune into our streaming network ABC News Live Tuesday on Hulu and Disney Plus' ABC News Live Prime with Linsey Davis.
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