25 U.S. Code § 3005 - Repatriation
If the lineal descendant, Indian tribe, or Native Hawaiian organization requests the return of culturally affiliated Native American cultural items, the Federal agency or museum shall expeditiously return such items unless such items are indispensable for completion of a specific scientific study, the outcome of which would be of major benefit to the United States. Such items shall be returned by no later than 90 days after the date on which the scientific study is completed.
If a known lineal descendant or an Indian tribe or Native Hawaiian organization requests the return of Native American unassociated funerary objects, sacred objects or objects of cultural patrimony pursuant to this chapter and presents evidence which, if standing alone before the introduction of evidence to the contrary, would support a finding that the Federal agency or museum did not have the right of possession, then such agency or museum shall return such objects unless it can overcome such inference and prove that it has a right of possession to the objects.
Any Federal agency or museum shall share what information it does possess regarding the object in question with the known lineal descendant, Indian tribe, or Native Hawaiian organization to assist in making a claim under this section.
Where there are multiple requests for repatriation of any cultural item and, after complying with the requirements of this chapter, the Federal agency or museum cannot clearly determine which requesting party is the most appropriate claimant, the agency or museum may retain such item until the requesting parties agree upon its disposition or the dispute is otherwise resolved pursuant to the provisions of this chapter or by a court of competent jurisdiction.
Any museum which repatriates any item in good faith pursuant to this chapter shall not be liable for claims by an aggrieved party or for claims of breach of fiduciary duty, public trust, or violations of state  law that are inconsistent with the provisions of this chapter.
 So in original. Probably should be capitalized.
This chapter, referred to in subsecs. (a)(3), (5)(C), (c), (e), and (f), was in the original “this Act”, meaning Pub. L. 101–601, Nov. 16, 1990, 104 Stat. 3048, known as the Native American Graves Protection and Repatriation Act, which is classified principally to this chapter. For complete classification of this Act to the Code, see Short Title note set out under section 3001 of this title and Tables.