25 USC 3005 - Repatriation

(a) Repatriation of Native American human remains and objects possessed or controlled by Federal agencies and museums 

(1) If, pursuant to section 3003 of this title, the cultural affiliation of Native American human remains and associated funerary objects with a particular Indian tribe or Native Hawaiian organization is established, then the Federal agency or museum, upon the request of a known lineal descendant of the Native American or of the tribe or organization and pursuant to subsections (b) and (e) of this section, shall expeditiously return such remains and associated funerary objects.
(2) If, pursuant to section 3004 of this title, the cultural affiliation with a particular Indian tribe or Native Hawaiian organization is shown with respect to unassociated funerary objects, sacred objects or objects of cultural patrimony, then the Federal agency or museum, upon the request of the Indian tribe or Native Hawaiian organization and pursuant to subsections (b), (c) and (e) of this section, shall expeditiously return such objects.
(3) The return of cultural items covered by this chapter shall be in consultation with the requesting lineal descendant or tribe or organization to determine the place and manner of delivery of such items.
(4) Where cultural affiliation of Native American human remains and funerary objects has not been established in an inventory prepared pursuant to section 3003 of this title, or the summary pursuant to section 3004 of this title, or where Native American human remains and funerary objects are not included upon any such inventory, then, upon request and pursuant to subsections (b) and (e) of this section and, in the case of unassociated funerary objects, subsection (c) of this section, such Native American human remains and funerary objects shall be expeditiously returned where the requesting Indian tribe or Native Hawaiian organization can show cultural affiliation by a preponderance of the evidence based upon geographical, kinship, biological, archaeological, anthropological, linguistic, folkloric, oral traditional, historical, or other relevant information or expert opinion.
(5) Upon request and pursuant to subsections (b), (c) and (e) of this section, sacred objects and objects of cultural patrimony shall be expeditiously returned where
(A) the requesting party is the direct lineal descendant of an individual who owned the sacred object;
(B) the requesting Indian tribe or Native Hawaiian organization can show that the object was owned or controlled by the tribe or organization; or
(C) the requesting Indian tribe or Native Hawaiian organization can show that the sacred object was owned or controlled by a member thereof, provided that in the case where a sacred object was owned by a member thereof, there are no identifiable lineal descendants of said member or the lineal descendants, upon notice, have failed to make a claim for the object under this chapter.
(b) Scientific study 
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.
(c) Standard of repatriation 
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.
(d) Sharing of information by Federal agencies and museums 
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.
(e) Competing claims 
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.
(f) Museum obligation 
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[1] law that are inconsistent with the provisions of this chapter.
[1] So in original. Probably should be capitalized.